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2025 · practice · Mathematics · Grade 12

Grade 12 Mathematics — KZN calculus & series

Notes

Answer all questions. Show a formula, substitution and a boxed answer with units. g = 9.8 m·s⁻². Calculators allowed.

90 min · 107 Marks · 30 questions

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Question breakdown

  1. 1.1 · 8 Marks · Area, sine and cosine rules

    ddx (x⁴)=

    Formulas

    Area=½ ab sin C

    Area rule

    c²=a²+b²−2ab cos C

    Cosine rule

    Notes: Power x⁴. Unknown: first derivative.

    How we got there

    Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.

    Explain in another language · 11

    1. What is the question asking?

    Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: ddx (x⁴) =

    Before any working — hunt first

    Given

    Numbers and units already in the sentence: no numbers yet — only a name, a diagram, or a worded unknown. Copy each one into a column. A name without a number is not given.

    Missing

    After you copy the given, the letter that still has no number is missing. The paper is pointing at: ddx (x⁴) =. Circle that word — that is the missing variable.

    Find

    We are required to find: ddx (x⁴) =. Write that as a symbol on the left, with a question mark, before you touch a formula.

    Calculate

    Write 4x³ with empty letters. Cross out every letter that already has a number. Calculate the letter that is still standing — that gives ddx (x⁴) =.

    In other words — as if you have never seen this before

    Power rule: bring the power down, drop the index by 1.

    2. What do we already know?

    Power x⁴. Unknown: first derivative.

    3. Which method — and why this one?

    Power rule: bring the power down, drop the index by 1.

    4. Step-by-step working

    1. 01 / 08

      Step A — Read the question twice

      Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.

      Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.

    2. 02 / 08

      Step A2 — Hunt: Given, Missing, Find, Calculate

      Given: Numbers and units already in the sentence: no numbers yet — only a name, a diagram, or a worded unknown. Copy each one into a column. A name without a number is not given. Missing: After you copy the given, the letter that still has no number is missing. The paper is pointing at: ddx (x⁴) =. Circle that word — that is the missing variable. Find: We are required to find: ddx (x⁴) =. Write that as a symbol on the left, with a question mark, before you touch a formula. Calculate: Write 4x³ with empty letters. Cross out every letter that already has a number. Calculate the letter that is still standing — that gives ddx (x⁴) =.

      Why this step: Do not name the letters yet. First hunt: what already has a number (Given), what has no number (Missing), the word the paper wants (Find), and which formula still contains the missing letter (Calculate).

    3. 03 / 08

      Step B — Write the given in a column

      Power x⁴. Unknown: first derivative.

      Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.

    4. 04 / 08

      Step C — Name the method in words

      Power rule: bring the power down, drop the index by 1.

      Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.

    5. 05 / 08

      Power rule

      n xⁿ⁻¹=4 x³.

      4x³

      Why this step: Write the formula before numbers. The memo awards a method mark even if a digit slips later.

    6. 06 / 08

      Step G — Sense-check the size

      Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.

      Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.

    7. 07 / 08

      Step F — Box the answer with its unit

      4x³

      Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.

    8. 08 / 08

      Step H — What the marker is looking for

      On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.

      Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.

    5. The answer

    4x³

    Copy onto your answer sheet — in this order

    Formula: 4x³

    Answer: 4x³

    6. Check it like a marker

    Integral of 4x³ is x⁴ + C. Inverse operations.

    7. A trap first-timers fall into

    x⁵5 is the integral, not the derivative. Read ddx.

  2. 1.2 · 10 Marks

    S_∞ of 16 + 8 + 4 + …

    Notes: a=16. r=816=12. |r| < 1 so S∞ exists.

    How we got there

    Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.

    Explain in another language · 11

    1. What is the question asking?

    Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: S_∞ of 16 + 8 + 4 + …

    Before any working — hunt first

    Given

    Numbers and units already in the sentence: 16 · 8 · 4. Copy each one into a column. A name without a number is not given.

    Missing

    After you copy the given, the letter that still has no number is missing. The paper is pointing at: S_∞ of 16 + 8 + 4 + …. Circle that word — that is the missing variable.

    Find

    We are required to find: S_∞ of 16 + 8 + 4 + …. Write that as a symbol on the left, with a question mark, before you touch a formula.

    Calculate

    Write r = 12 with empty letters. Cross out every letter that already has a number. Calculate the letter that is still standing — that gives S_∞ of 16 + 8 + 4 + ….

    In other words — as if you have never seen this before

    S_∞ = a(1 − r) for |r| < 1.

    2. What do we already know?

    a=16. r=816=12. |r| < 1 so S∞ exists.

    3. Which method — and why this one?

    S_∞ = a(1 − r) for |r| < 1.

    4. Step-by-step working

    1. 01 / 05

      Name r

      r=12. |r| < 1, so it converges.

      r=12

      Why this step: One job per line so you can find a slip, and so a marker can follow the marks.

    2. 02 / 05

      Formula

      S=16(1 − 1/2)=16(1/2)=32.

      S∞=32

      Why this step: Write the formula before numbers. The memo awards a method mark even if a digit slips later.

    3. 03 / 05

      Step G — Sense-check the size

      Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.

      Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.

    4. 04 / 05

      Step F — Box the answer with its unit

      32

      Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.

    5. 05 / 05

      Step H — What the marker is looking for

      On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.

      Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.

    5. The answer

    32

    Copy onto your answer sheet — in this order

    Formula: r=12

    Answer: 32

    6. Check it like a marker

    16+8+4+2+1+… approaches 32, never 28.

    7. A trap first-timers fall into

    Adding the first three terms only (28) is not S_∞.

  3. 2.1 · 10 Marks · First principles of differentiation

    f(x)=x²−6x. Stationary x=

    Formulas

    f'(x)=limh→0[f(x+h) − f(x)]h

    Definition of the derivative

    Notes: f(x)=x²−6x. Unknown: x where f'=0.

    How we got there

    Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.

    Explain in another language · 11

    1. What is the question asking?

    Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: f(x)=x²−6x. Stationary x =

    Before any working — hunt first

    Given

    Numbers and units already in the sentence: 6x. Copy each one into a column. A name without a number is not given.

    Missing

    After you copy the given, the letter that still has no number is missing. The paper is pointing at: Stationary x =. Circle that word — that is the missing variable.

    Find

    We are required to find: Stationary x =. Write that as a symbol on the left, with a question mark, before you touch a formula.

    Calculate

    Write f' = 2x−6 with empty letters. Cross out every letter that already has a number. Calculate the letter that is still standing — that gives Stationary x =.

    In other words — as if you have never seen this before

    Stationary ⇒ f'(x) = 0. Differentiate first.

    2. What do we already know?

    f(x)=x²−6x. Unknown: x where f'=0.

    3. Which method — and why this one?

    Stationary ⇒ f'(x) = 0. Differentiate first.

    4. Step-by-step working

    1. 01 / 05

      Differentiate

      f'=2x−6.

      f'=2x−6

      Why this step: Write the formula before numbers. The memo awards a method mark even if a digit slips later.

    2. 02 / 05

      Set to zero

      2x−6=0→x=3.

      x=3

      Why this step: One job per line so you can find a slip, and so a marker can follow the marks.

    3. 03 / 05

      Step G — Sense-check the size

      Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.

      Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.

    4. 04 / 05

      Step F — Box the answer with its unit

      3

      Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.

    5. 05 / 05

      Step H — What the marker is looking for

      On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.

      Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.

    5. The answer

    3

    Copy onto your answer sheet — in this order

    Formula: f'=2x−6

    Answer: 3

    6. Check it like a marker

    f''=2 > 0, a minimum. f(3)=9−18=−9.

    7. A trap first-timers fall into

    x = 6 is where f(x)=0 (a root), not where the gradient is zero.

  4. 2.2 · 12 Marks

    log₁₀ 100=

    Notes: log base 10 of 100.

    How we got there

    Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.

    Explain in another language · 11

    1. What is the question asking?

    Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: log₁₀ 100 =

    Before any working — hunt first

    Given

    Numbers and units already in the sentence: 100. Copy each one into a column. A name without a number is not given.

    Missing

    After you copy the given, the letter that still has no number is missing. The paper is pointing at: log₁₀ 100 =. Circle that word — that is the missing variable.

    Find

    We are required to find: log₁₀ 100 =. Write that as a symbol on the left, with a question mark, before you touch a formula.

    Calculate

    Write 2 with empty letters. Cross out every letter that already has a number. Calculate the letter that is still standing — that gives log₁₀ 100 =.

    In other words — as if you have never seen this before

    logb a=x means bx=a. 10²=100.

    2. What do we already know?

    log base 10 of 100.

    3. Which method — and why this one?

    logb a=x means bx=a. 10²=100.

    4. Step-by-step working

    1. 01 / 08

      Step A — Read the question twice

      Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.

      Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.

    2. 02 / 08

      Step A2 — Hunt: Given, Missing, Find, Calculate

      Given: Numbers and units already in the sentence: 100. Copy each one into a column. A name without a number is not given. Missing: After you copy the given, the letter that still has no number is missing. The paper is pointing at: log₁₀ 100 =. Circle that word — that is the missing variable. Find: We are required to find: log₁₀ 100 =. Write that as a symbol on the left, with a question mark, before you touch a formula. Calculate: Write 2 with empty letters. Cross out every letter that already has a number. Calculate the letter that is still standing — that gives log₁₀ 100 =.

      Why this step: Do not name the letters yet. First hunt: what already has a number (Given), what has no number (Missing), the word the paper wants (Find), and which formula still contains the missing letter (Calculate).

    3. 03 / 08

      Step B — Write the given in a column

      log base 10 of 100.

      Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.

    4. 04 / 08

      Step C — Name the method in words

      logb a=x means bx=a. 10²=100.

      Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.

    5. 05 / 08

      Rewrite as a power

      10x=100=10²→x=2.

      2

      Why this step: Write the formula before numbers. The memo awards a method mark even if a digit slips later.

    6. 06 / 08

      Step G — Sense-check the size

      Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.

      Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.

    7. 07 / 08

      Step F — Box the answer with its unit

      2

      Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.

    8. 08 / 08

      Step H — What the marker is looking for

      On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.

      Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.

    5. The answer

    2

    Copy onto your answer sheet — in this order

    Formula: 2

    Answer: 2

    6. Check it like a marker

    10² is 100. Count the zeros: 2.

    7. A trap first-timers fall into

    Writing 10 treats log as a linear scale.

  5. 5 · 3 Marks · Arithmetic & geometric series

    Geometric a=27, r=13. S∞=

    Formulas

    Tₙ=a rⁿ⁻¹

    Geometric nth term — exponent is n minus 1

    Sₙ=n2 [2a + (n−1)d]

    Arithmetic sum

    Sₙ=a(rⁿ − 1)(r − 1), r ≠ 1

    Geometric sum

    Notes: First term a = 27. Ratio r = 13. Infinite geometric series. Unknown: S_∞.

    How we got there

    Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.

    Explain in another language · 11

    1. What is the question asking?

    Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: Geometric a = 27, r = 13. S_∞ =

    Before any working — hunt first

    Given

    Numbers and units already in the sentence: 27 · 1/ · 3. Copy each one into a column. A name without a number is not given.

    Missing

    After you copy the given, the letter that still has no number is missing. The paper is pointing at: S_∞ =. Circle that word — that is the missing variable.

    Find

    We are required to find: S_∞ =. Write that as a symbol on the left, with a question mark, before you touch a formula.

    Calculate

    Write |r| < 1 with empty letters. Cross out every letter that already has a number. Calculate the letter that is still standing — that gives S_∞ =.

    In other words — as if you have never seen this before

    It converges only if |r| < 1. Here |13| < 1, so S_∞ = a(1 − r).

    2. What do we already know?

    First term a = 27. Ratio r = 13. Infinite geometric series. Unknown: S_∞.

    3. Which method — and why this one?

    It converges only if |r| < 1. Here |13| < 1, so S_∞ = a(1 − r).

    4. Step-by-step working

    1. 01 / 05

      Test |r|

      |13| = 13 which is less than 1. The terms shrink (27, 9, 3, 1, …) so a finite sum exists.

      |r| < 1

      Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.

    2. 02 / 05

      Apply S_∞

      S∞=27(1 − 1/3)=27(2/3)=27×32=40.5.

      S∞=a(1−r)=40.5

      Why this step: Dividing by a fraction is multiplying by the flip. 27 ÷ (2/3) = 27 × 3/2.

    3. 03 / 05

      Step G — Sense-check the size

      Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.

      Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.

    4. 04 / 05

      Step F — Box the answer with its unit

      40.5

      Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.

    5. 05 / 05

      Step H — What the marker is looking for

      On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.

      Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.

    5. The answer

    40.5

    Copy onto your answer sheet — in this order

    Formula: |r| < 1

    Answer: 40.5

    6. Check it like a marker

    27+9+3+1+13+… is clearly more than 27+9=36 and less than 27+27=54. 40.5 sits in the middle.

    7. A trap first-timers fall into

    Writing ∞ because “it never stops.” It never stops, but the leftover becomes tiny. That is what |r|<1 means.

  6. 6 · 2 Marks

    r=−0.9 means

    How we got there

    Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.

    Explain in another language · 11

    1. What is the question asking?

    Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: r = −0.9 means

    Before any working — hunt first

    Given

    Numbers and units already in the sentence: 0.9 means. Copy each one into a column. A name without a number is not given.

    Missing

    After you copy the given, the letter that still has no number is missing. The paper is pointing at: 9 means. Circle that word — that is the missing variable.

    Find

    We are required to find: 9 means. Write that as a symbol on the left, with a question mark, before you touch a formula.

    Calculate

    What we need to calculate: Close to −1: strong negative. Then substitute the given, one line at a time, to get 9 means.

    In other words — as if you have never seen this before

    Close to −1: strong negative.

    2. What do we already know?

    Copy these onto the left of your page, one per line, with units: 0.9 means. Mixing cm with m, or minutes with seconds, loses a method mark.

    3. Which method — and why this one?

    Close to −1: strong negative.

    4. Step-by-step working

    1. 01 / 08

      Step A — Read the question twice

      Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.

      Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.

    2. 02 / 08

      Step A2 — Hunt: Given, Missing, Find, Calculate

      Given: Numbers and units already in the sentence: 0.9 means. Copy each one into a column. A name without a number is not given. Missing: After you copy the given, the letter that still has no number is missing. The paper is pointing at: 9 means. Circle that word — that is the missing variable. Find: We are required to find: 9 means. Write that as a symbol on the left, with a question mark, before you touch a formula. Calculate: What we need to calculate: Close to −1: strong negative. Then substitute the given, one line at a time, to get 9 means.

      Why this step: Do not name the letters yet. First hunt: what already has a number (Given), what has no number (Missing), the word the paper wants (Find), and which formula still contains the missing letter (Calculate).

    3. 03 / 08

      Step B — Write the given in a column

      Copy these onto the left of your page, one per line, with units: 0.9 means. Mixing cm with m, or minutes with seconds, loses a method mark.

      Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.

    4. 04 / 08

      Step C — Name the method in words

      Close to −1: strong negative.

      Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.

    5. 05 / 08

      Working

      Close to −1: strong negative.

      Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.

    6. 06 / 08

      Step G — Sense-check the size

      Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.

      Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.

    7. 07 / 08

      Step F — Box the answer with its unit

      strong negative linear correlation

      Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.

    8. 08 / 08

      Step H — What the marker is looking for

      On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.

      Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.

    5. The answer

    strong negative linear correlation

    Copy onto your answer sheet — in this order

    Answer: strong negative linear correlation

    6. Check it like a marker

    Does your answer appear as one of the options? Do the units match what was asked (m, N, J, °)? If you put the number back into the original equation, does it still hold? Estimate: is the size sensible?

    7. A trap first-timers fall into

    First-timers often grab the first formula they remember, mix units (cm with m, minutes with seconds), or drop a minus sign. Write the formula in words first: “this equals that, because…”

  7. 7 · 2 Marks

    5!=

    How we got there

    Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.

    Explain in another language · 11

    1. What is the question asking?

    Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: 5! =

    Before any working — hunt first

    Given

    Numbers and units already in the sentence: 5. Copy each one into a column. A name without a number is not given.

    Missing

    After you copy the given, the letter that still has no number is missing. The paper is pointing at: =. Circle that word — that is the missing variable.

    Find

    We are required to find: =. Write that as a symbol on the left, with a question mark, before you touch a formula.

    Calculate

    What we need to calculate: 5×4×3×2×1=120. Then substitute the given, one line at a time, to get =.

    In other words — as if you have never seen this before

    5×4×3×2×1=120.

    2. What do we already know?

    Copy these onto the left of your page, one per line, with units: 5. Mixing cm with m, or minutes with seconds, loses a method mark.

    3. Which method — and why this one?

    5×4×3×2×1=120.

    4. Step-by-step working

    1. 01 / 08

      Step A — Read the question twice

      Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.

      Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.

    2. 02 / 08

      Step A2 — Hunt: Given, Missing, Find, Calculate

      Given: Numbers and units already in the sentence: 5. Copy each one into a column. A name without a number is not given. Missing: After you copy the given, the letter that still has no number is missing. The paper is pointing at: =. Circle that word — that is the missing variable. Find: We are required to find: =. Write that as a symbol on the left, with a question mark, before you touch a formula. Calculate: What we need to calculate: 5×4×3×2×1=120. Then substitute the given, one line at a time, to get =.

      Why this step: Do not name the letters yet. First hunt: what already has a number (Given), what has no number (Missing), the word the paper wants (Find), and which formula still contains the missing letter (Calculate).

    3. 03 / 08

      Step B — Write the given in a column

      Copy these onto the left of your page, one per line, with units: 5. Mixing cm with m, or minutes with seconds, loses a method mark.

      Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.

    4. 04 / 08

      Step C — Name the method in words

      5×4×3×2×1=120.

      Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.

    5. 05 / 08

      Working

      5×4×3×2×1=120.

      Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.

    6. 06 / 08

      Step G — Sense-check the size

      Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.

      Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.

    7. 07 / 08

      Step F — Box the answer with its unit

      120

      Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.

    8. 08 / 08

      Step H — What the marker is looking for

      On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.

      Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.

    5. The answer

    120

    Copy onto your answer sheet — in this order

    Answer: 120

    6. Check it like a marker

    Does your answer appear as one of the options? Do the units match what was asked (m, N, J, °)? If you put the number back into the original equation, does it still hold? Estimate: is the size sensible?

    7. A trap first-timers fall into

    First-timers often grab the first formula they remember, mix units (cm with m, minutes with seconds), or drop a minus sign. Write the formula in words first: “this equals that, because…”

  8. 8 · 3 Marks · Compound angles

    sin 75°=

    hbθ

    Formulas

    sin(A + B)=sin A cos B+cos A sin B

    Sine compound

    How we got there

    Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.

    Explain in another language · 11

    1. What is the question asking?

    Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: sin 75° =

    Before any working — hunt first

    Given

    Numbers and units already in the sentence: 75°. Copy each one into a column. A name without a number is not given.

    Missing

    After you copy the given, the letter that still has no number is missing. The paper is pointing at: sin 75° =. Circle that word — that is the missing variable.

    Find

    We are required to find: sin 75° =. Write that as a symbol on the left, with a question mark, before you touch a formula.

    Calculate

    What we need to calculate: sin(45+30)=sin45cos30+cos45sin30. Then substitute the given, one line at a time, to get sin 75° =.

    In other words — as if you have never seen this before

    sin(45+30)=sin45cos30+cos45sin30.

    2. What do we already know?

    Copy these onto the left of your page, one per line, with units: 75°. Mixing cm with m, or minutes with seconds, loses a method mark.

    3. Which method — and why this one?

    sin(45+30)=sin45cos30+cos45sin30.

    4. Step-by-step working

    1. 01 / 08

      Step A — Read the question twice

      Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.

      Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.

    2. 02 / 08

      Step A2 — Hunt: Given, Missing, Find, Calculate

      Given: Numbers and units already in the sentence: 75°. Copy each one into a column. A name without a number is not given. Missing: After you copy the given, the letter that still has no number is missing. The paper is pointing at: sin 75° =. Circle that word — that is the missing variable. Find: We are required to find: sin 75° =. Write that as a symbol on the left, with a question mark, before you touch a formula. Calculate: What we need to calculate: sin(45+30)=sin45cos30+cos45sin30. Then substitute the given, one line at a time, to get sin 75° =.

      Why this step: Do not name the letters yet. First hunt: what already has a number (Given), what has no number (Missing), the word the paper wants (Find), and which formula still contains the missing letter (Calculate).

    3. 03 / 08

      Step B — Write the given in a column

      Copy these onto the left of your page, one per line, with units: 75°. Mixing cm with m, or minutes with seconds, loses a method mark.

      Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.

    4. 04 / 08

      Step C — Name the method in words

      sin(45+30)=sin45cos30+cos45sin30.

      Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.

    5. 05 / 08

      Working

      sin(45+30)=sin45cos30+cos45sin30.

      Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.

    6. 06 / 08

      Step G — Sense-check the size

      Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.

      Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.

    7. 07 / 08

      Step F — Box the answer with its unit

      (√6+√2)4

      Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.

    8. 08 / 08

      Step H — What the marker is looking for

      On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.

      Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.

    5. The answer

    (√6+√2)4

    Copy onto your answer sheet — in this order

    Answer: (√6+√2)4

    6. Check it like a marker

    Does your answer appear as one of the options? Do the units match what was asked (m, N, J, °)? If you put the number back into the original equation, does it still hold? Estimate: is the size sensible?

    7. A trap first-timers fall into

    First-timers often grab the first formula they remember, mix units (cm with m, minutes with seconds), or drop a minus sign. Write the formula in words first: “this equals that, because…”

  9. 9 · 3 Marks · Regression & correlation

    r=0.2 means

    Formulas

    ŷ=a+bx

    Least-squares line

    −1 ≤ r ≤ 1

    Pearson’s r

    How we got there

    Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.

    Explain in another language · 11

    1. What is the question asking?

    Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: r = 0.2 means

    Before any working — hunt first

    Given

    Numbers and units already in the sentence: 0.2 means. Copy each one into a column. A name without a number is not given.

    Missing

    After you copy the given, the letter that still has no number is missing. The paper is pointing at: 2 means. Circle that word — that is the missing variable.

    Find

    We are required to find: 2 means. Write that as a symbol on the left, with a question mark, before you touch a formula.

    Calculate

    What we need to calculate: weak positive correlation. Then substitute the given, one line at a time, to get 2 means.

    In other words — as if you have never seen this before

    weak positive correlation

    2. What do we already know?

    Copy these onto the left of your page, one per line, with units: 0.2 means. Mixing cm with m, or minutes with seconds, loses a method mark.

    3. Which method — and why this one?

    weak positive correlation

    4. Step-by-step working

    1. 01 / 08

      Step A — Read the question twice

      Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.

      Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.

    2. 02 / 08

      Step A2 — Hunt: Given, Missing, Find, Calculate

      Given: Numbers and units already in the sentence: 0.2 means. Copy each one into a column. A name without a number is not given. Missing: After you copy the given, the letter that still has no number is missing. The paper is pointing at: 2 means. Circle that word — that is the missing variable. Find: We are required to find: 2 means. Write that as a symbol on the left, with a question mark, before you touch a formula. Calculate: What we need to calculate: weak positive correlation. Then substitute the given, one line at a time, to get 2 means.

      Why this step: Do not name the letters yet. First hunt: what already has a number (Given), what has no number (Missing), the word the paper wants (Find), and which formula still contains the missing letter (Calculate).

    3. 03 / 08

      Step B — Write the given in a column

      Copy these onto the left of your page, one per line, with units: 0.2 means. Mixing cm with m, or minutes with seconds, loses a method mark.

      Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.

    4. 04 / 08

      Step C — Name the method in words

      weak positive correlation

      Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.

    5. 05 / 08

      Reason

      Close to 0, positive.

      Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.

    6. 06 / 08

      Step G — Sense-check the size

      Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.

      Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.

    7. 07 / 08

      Step F — Box the answer with its unit

      weak positive correlation

      Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.

    8. 08 / 08

      Step H — What the marker is looking for

      On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.

      Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.

    5. The answer

    weak positive correlation

    Copy onto your answer sheet — in this order

    Answer: weak positive correlation

    6. Check it like a marker

    Does your answer appear as one of the options? Do the units match what was asked (m, N, J, °)? If you put the number back into the original equation, does it still hold? Estimate: is the size sensible?

    7. A trap first-timers fall into

    First-timers often grab the first formula they remember, mix units (cm with m, minutes with seconds), or drop a minus sign. Write the formula in words first: “this equals that, because…”

  10. 10 · 3 Marks

    6C2=

    How we got there

    Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.

    Explain in another language · 11

    1. What is the question asking?

    Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: 6C2 =

    Before any working — hunt first

    Given

    Numbers and units already in the sentence: 6C · 2. Copy each one into a column. A name without a number is not given.

    Missing

    After you copy the given, the letter that still has no number is missing. The paper is pointing at: 6C2 =. Circle that word — that is the missing variable.

    Find

    We are required to find: 6C2 =. Write that as a symbol on the left, with a question mark, before you touch a formula.

    Calculate

    What we need to calculate: 15. Then substitute the given, one line at a time, to get 6C2 =.

    In other words — as if you have never seen this before

    15

    2. What do we already know?

    Copy these onto the left of your page, one per line, with units: 6C · 2. Mixing cm with m, or minutes with seconds, loses a method mark.

    3. Which method — and why this one?

    15

    4. Step-by-step working

    1. 01 / 08

      Step A — Read the question twice

      Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.

      Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.

    2. 02 / 08

      Step A2 — Hunt: Given, Missing, Find, Calculate

      Given: Numbers and units already in the sentence: 6C · 2. Copy each one into a column. A name without a number is not given. Missing: After you copy the given, the letter that still has no number is missing. The paper is pointing at: 6C2 =. Circle that word — that is the missing variable. Find: We are required to find: 6C2 =. Write that as a symbol on the left, with a question mark, before you touch a formula. Calculate: What we need to calculate: 15. Then substitute the given, one line at a time, to get 6C2 =.

      Why this step: Do not name the letters yet. First hunt: what already has a number (Given), what has no number (Missing), the word the paper wants (Find), and which formula still contains the missing letter (Calculate).

    3. 03 / 08

      Step B — Write the given in a column

      Copy these onto the left of your page, one per line, with units: 6C · 2. Mixing cm with m, or minutes with seconds, loses a method mark.

      Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.

    4. 04 / 08

      Step C — Name the method in words

      15

      Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.

    5. 05 / 08

      Working

      6! / (2! 4!) = (6 × 5) / 2 = 15. Combinations do not care about order — that is why we divide by 2!.

      Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.

    6. 06 / 08

      Step G — Sense-check the size

      Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.

      Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.

    7. 07 / 08

      Step F — Box the answer with its unit

      15

      Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.

    8. 08 / 08

      Step H — What the marker is looking for

      On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.

      Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.

    5. The answer

    15

    Copy onto your answer sheet — in this order

    Answer: 15

    6. Check it like a marker

    Does your answer appear as one of the options? Do the units match what was asked (m, N, J, °)? If you put the number back into the original equation, does it still hold? Estimate: is the size sensible?

    7. A trap first-timers fall into

    First-timers often grab the first formula they remember, mix units (cm with m, minutes with seconds), or drop a minus sign. Write the formula in words first: “this equals that, because…”

  11. 11 · 2 Marks

    log₁₀ 1000=

    How we got there

    Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.

    Explain in another language · 11

    1. What is the question asking?

    Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: log₁₀ 1000 =

    Before any working — hunt first

    Given

    Numbers and units already in the sentence: 1000. Copy each one into a column. A name without a number is not given.

    Missing

    After you copy the given, the letter that still has no number is missing. The paper is pointing at: log₁₀ 1000 =. Circle that word — that is the missing variable.

    Find

    We are required to find: log₁₀ 1000 =. Write that as a symbol on the left, with a question mark, before you touch a formula.

    Calculate

    What we need to calculate: 10³ = 1000. Then substitute the given, one line at a time, to get log₁₀ 1000 =.

    In other words — as if you have never seen this before

    10³=1000.

    2. What do we already know?

    Copy these onto the left of your page, one per line, with units: 1000. Mixing cm with m, or minutes with seconds, loses a method mark.

    3. Which method — and why this one?

    10³=1000.

    4. Step-by-step working

    1. 01 / 08

      Step A — Read the question twice

      Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.

      Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.

    2. 02 / 08

      Step A2 — Hunt: Given, Missing, Find, Calculate

      Given: Numbers and units already in the sentence: 1000. Copy each one into a column. A name without a number is not given. Missing: After you copy the given, the letter that still has no number is missing. The paper is pointing at: log₁₀ 1000 =. Circle that word — that is the missing variable. Find: We are required to find: log₁₀ 1000 =. Write that as a symbol on the left, with a question mark, before you touch a formula. Calculate: What we need to calculate: 10³ = 1000. Then substitute the given, one line at a time, to get log₁₀ 1000 =.

      Why this step: Do not name the letters yet. First hunt: what already has a number (Given), what has no number (Missing), the word the paper wants (Find), and which formula still contains the missing letter (Calculate).

    3. 03 / 08

      Step B — Write the given in a column

      Copy these onto the left of your page, one per line, with units: 1000. Mixing cm with m, or minutes with seconds, loses a method mark.

      Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.

    4. 04 / 08

      Step C — Name the method in words

      10³=1000.

      Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.

    5. 05 / 08

      Working

      10³=1000.

      Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.

    6. 06 / 08

      Step G — Sense-check the size

      Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.

      Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.

    7. 07 / 08

      Step F — Box the answer with its unit

      3

      Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.

    8. 08 / 08

      Step H — What the marker is looking for

      On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.

      Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.

    5. The answer

    3

    Copy onto your answer sheet — in this order

    Answer: 3

    6. Check it like a marker

    Does your answer appear as one of the options? Do the units match what was asked (m, N, J, °)? If you put the number back into the original equation, does it still hold? Estimate: is the size sensible?

    7. A trap first-timers fall into

    First-timers often grab the first formula they remember, mix units (cm with m, minutes with seconds), or drop a minus sign. Write the formula in words first: “this equals that, because…”

  12. 12 · 3 Marks · Remainder & factor theorem

    Remainder when x³ − 2x + 1 is divided by (x − 1) is

    hbθ

    Formulas

    f(a)=0⇔(x − a) | f(x)

    Factor theorem

    How we got there

    Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.

    Explain in another language · 11

    1. What is the question asking?

    Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: Remainder when x³ − 2x + 1 is divided by (x − 1) is

    In other words — as if you have never seen this before

    Remainder theorem: f(1)=1−2+1=0. (x−1) is a factor.

    2. What do we already know?

    Copy these onto the left of your page, one per line, with units: 2x · 1 is · 1. Mixing cm with m, or minutes with seconds, loses a method mark.

    3. Which method — and why this one?

    Remainder theorem: f(1)=1−2+1=0. (x−1) is a factor.

    4. Step-by-step working

    1. 01 / 07

      Step A — Read the question twice

      Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.

      Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.

    2. 02 / 07

      Step B — Write the given in a column

      Copy these onto the left of your page, one per line, with units: 2x · 1 is · 1. Mixing cm with m, or minutes with seconds, loses a method mark.

      Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.

    3. 03 / 07

      Step C — Name the method in words

      Remainder theorem: f(1)=1−2+1=0. (x−1) is a factor.

      Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.

    4. 04 / 07

      Working

      Remainder theorem: f(1)=1−2+1=0. (x−1) is a factor.

      Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.

    5. 05 / 07

      Step G — Sense-check the size

      Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.

      Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.

    6. 06 / 07

      Step F — Box the answer with its unit

      0

      Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.

    7. 07 / 07

      Step H — What the marker is looking for

      On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.

      Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.

    5. The answer

    0

    Copy onto your answer sheet — in this order

    Answer: 0

    6. Check it like a marker

    Does your answer appear as one of the options? Do the units match what was asked (m, N, J, °)? If you put the number back into the original equation, does it still hold? Estimate: is the size sensible?

    7. A trap first-timers fall into

    First-timers often grab the first formula they remember, mix units (cm with m, minutes with seconds), or drop a minus sign. Write the formula in words first: “this equals that, because…”

  13. 13 · 2 Marks

    If f(x) = x + 4, f⁻¹(x) =

    How we got there

    Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.

    Explain in another language · 11

    1. What is the question asking?

    Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: If f(x) = x + 4, f⁻¹(x) =

    Before any working — hunt first

    Given

    Numbers and units already in the sentence: 4. Copy each one into a column. A name without a number is not given.

    Missing

    After you copy the given, the letter that still has no number is missing. The paper is pointing at: If f(x) = x + 4, f⁻¹(x) =. Circle that word — that is the missing variable.

    Find

    We are required to find: If f(x) = x + 4, f⁻¹(x) =. Write that as a symbol on the left, with a question mark, before you touch a formula.

    Calculate

    What we need to calculate: Swap and subtract 4. Then substitute the given, one line at a time, to get If f(x) = x + 4, f⁻¹(x) =.

    In other words — as if you have never seen this before

    Swap and subtract 4.

    2. What do we already know?

    Copy these onto the left of your page, one per line, with units: 4. Mixing cm with m, or minutes with seconds, loses a method mark.

    3. Which method — and why this one?

    Swap and subtract 4.

    4. Step-by-step working

    1. 01 / 08

      Step A — Read the question twice

      Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.

      Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.

    2. 02 / 08

      Step A2 — Hunt: Given, Missing, Find, Calculate

      Given: Numbers and units already in the sentence: 4. Copy each one into a column. A name without a number is not given. Missing: After you copy the given, the letter that still has no number is missing. The paper is pointing at: If f(x) = x + 4, f⁻¹(x) =. Circle that word — that is the missing variable. Find: We are required to find: If f(x) = x + 4, f⁻¹(x) =. Write that as a symbol on the left, with a question mark, before you touch a formula. Calculate: What we need to calculate: Swap and subtract 4. Then substitute the given, one line at a time, to get If f(x) = x + 4, f⁻¹(x) =.

      Why this step: Do not name the letters yet. First hunt: what already has a number (Given), what has no number (Missing), the word the paper wants (Find), and which formula still contains the missing letter (Calculate).

    3. 03 / 08

      Step B — Write the given in a column

      Copy these onto the left of your page, one per line, with units: 4. Mixing cm with m, or minutes with seconds, loses a method mark.

      Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.

    4. 04 / 08

      Step C — Name the method in words

      Swap and subtract 4.

      Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.

    5. 05 / 08

      Working

      Swap and subtract 4.

      Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.

    6. 06 / 08

      Step G — Sense-check the size

      Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.

      Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.

    7. 07 / 08

      Step F — Box the answer with its unit

      x − 4

      Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.

    8. 08 / 08

      Step H — What the marker is looking for

      On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.

      Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.

    5. The answer

    x − 4

    Copy onto your answer sheet — in this order

    Answer: x − 4

    6. Check it like a marker

    Does your answer appear as one of the options? Do the units match what was asked (m, N, J, °)? If you put the number back into the original equation, does it still hold? Estimate: is the size sensible?

    7. A trap first-timers fall into

    First-timers often grab the first formula they remember, mix units (cm with m, minutes with seconds), or drop a minus sign. Write the formula in words first: “this equals that, because…”

  14. 14 · 2 Marks · Circles & tangents

    A tangent is perpendicular to the

    Formulas

    (x − a)²+(y − b)²=r²

    Circle

    mradius×mtangent=−1

    Tangent ⟂ radius

    How we got there

    Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.

    Explain in another language · 11

    1. What is the question asking?

    Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: A tangent is perpendicular to the

    Before any working — hunt first

    Given

    Numbers and units already in the sentence: no numbers yet — only a name, a diagram, or a worded unknown. Copy each one into a column. A name without a number is not given.

    Missing

    After you copy the given, the letter that still has no number is missing. The paper is pointing at: A tangent is perpendicular to the. Circle that word — that is the missing variable.

    Find

    We are required to find: A tangent is perpendicular to the. Write that as a symbol on the left, with a question mark, before you touch a formula.

    Calculate

    What we need to calculate: Classic circle theorem in analytical form. Then substitute the given, one line at a time, to get A tangent is perpendicular to the.

    In other words — as if you have never seen this before

    Classic circle theorem in analytical form.

    2. What do we already know?

    Copy these onto the left of your page, one per line, with units: every number and its unit in the sentence. Mixing cm with m, or minutes with seconds, loses a method mark.

    3. Which method — and why this one?

    Classic circle theorem in analytical form.

    4. Step-by-step working

    1. 01 / 08

      Step A — Read the question twice

      Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.

      Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.

    2. 02 / 08

      Step A2 — Hunt: Given, Missing, Find, Calculate

      Given: Numbers and units already in the sentence: no numbers yet — only a name, a diagram, or a worded unknown. Copy each one into a column. A name without a number is not given. Missing: After you copy the given, the letter that still has no number is missing. The paper is pointing at: A tangent is perpendicular to the. Circle that word — that is the missing variable. Find: We are required to find: A tangent is perpendicular to the. Write that as a symbol on the left, with a question mark, before you touch a formula. Calculate: What we need to calculate: Classic circle theorem in analytical form. Then substitute the given, one line at a time, to get A tangent is perpendicular to the.

      Why this step: Do not name the letters yet. First hunt: what already has a number (Given), what has no number (Missing), the word the paper wants (Find), and which formula still contains the missing letter (Calculate).

    3. 03 / 08

      Step B — Write the given in a column

      Copy these onto the left of your page, one per line, with units: every number and its unit in the sentence. Mixing cm with m, or minutes with seconds, loses a method mark.

      Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.

    4. 04 / 08

      Step C — Name the method in words

      Classic circle theorem in analytical form.

      Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.

    5. 05 / 08

      Working

      Classic circle theorem in analytical form.

      Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.

    6. 06 / 08

      Step G — Sense-check the size

      Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.

      Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.

    7. 07 / 08

      Step F — Box the answer with its unit

      radius at the point of contact

      Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.

    8. 08 / 08

      Step H — What the marker is looking for

      On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.

      Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.

    5. The answer

    radius at the point of contact

    Copy onto your answer sheet — in this order

    Answer: radius at the point of contact

    6. Check it like a marker

    Does your answer appear as one of the options? Do the units match what was asked (m, N, J, °)? If you put the number back into the original equation, does it still hold? Estimate: is the size sensible?

    7. A trap first-timers fall into

    First-timers often grab the first formula they remember, mix units (cm with m, minutes with seconds), or drop a minus sign. Write the formula in words first: “this equals that, because…”

  15. 15 · 2 Marks · Arithmetic & geometric series

    S_∞ of a geometric series exists only when

    Formulas

    Tₙ=a rⁿ⁻¹

    Geometric nth term — exponent is n minus 1

    Sₙ=n2 [2a + (n−1)d]

    Arithmetic sum

    Sₙ=a(rⁿ − 1)(r − 1), r ≠ 1

    Geometric sum

    How we got there

    Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.

    Explain in another language · 11

    1. What is the question asking?

    Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: S_∞ of a geometric series exists only when

    In other words — as if you have never seen this before

    Terms must shrink. |r| ≥ 1 ⇒ the series diverges.

    2. What do we already know?

    Copy these onto the left of your page, one per line, with units: every number and its unit in the sentence. Mixing cm with m, or minutes with seconds, loses a method mark.

    3. Which method — and why this one?

    Terms must shrink. |r| ≥ 1 ⇒ the series diverges.

    4. Step-by-step working

    1. 01 / 07

      Step A — Read the question twice

      Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.

      Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.

    2. 02 / 07

      Step B — Write the given in a column

      Copy these onto the left of your page, one per line, with units: every number and its unit in the sentence. Mixing cm with m, or minutes with seconds, loses a method mark.

      Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.

    3. 03 / 07

      Step C — Name the method in words

      Terms must shrink. |r| ≥ 1 ⇒ the series diverges.

      Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.

    4. 04 / 07

      Working

      Terms must shrink. |r| ≥ 1 ⇒ the series diverges.

      Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.

    5. 05 / 07

      Step G — Sense-check the size

      Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.

      Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.

    6. 06 / 07

      Step F — Box the answer with its unit

      |r| < 1

      Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.

    7. 07 / 07

      Step H — What the marker is looking for

      On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.

      Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.

    5. The answer

    |r| < 1

    Copy onto your answer sheet — in this order

    Answer: |r| < 1

    6. Check it like a marker

    Does your answer appear as one of the options? Do the units match what was asked (m, N, J, °)? If you put the number back into the original equation, does it still hold? Estimate: is the size sensible?

    7. A trap first-timers fall into

    First-timers often grab the first formula they remember, mix units (cm with m, minutes with seconds), or drop a minus sign. Write the formula in words first: “this equals that, because…”

  16. 16 · 2 Marks · Arithmetic & geometric series

    Geometric a=8, r=12. S∞=

    Formulas

    Tₙ=a rⁿ⁻¹

    Geometric nth term — exponent is n minus 1

    Sₙ=n2 [2a + (n−1)d]

    Arithmetic sum

    Sₙ=a(rⁿ − 1)(r − 1), r ≠ 1

    Geometric sum

    How we got there

    Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.

    Explain in another language · 11

    1. What is the question asking?

    Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: Geometric a = 8, r = 12. S_∞ =

    Before any working — hunt first

    Given

    Numbers and units already in the sentence: 8 · 1/ · 2. Copy each one into a column. A name without a number is not given.

    Missing

    After you copy the given, the letter that still has no number is missing. The paper is pointing at: S_∞ =. Circle that word — that is the missing variable.

    Find

    We are required to find: S_∞ =. Write that as a symbol on the left, with a question mark, before you touch a formula.

    Calculate

    What we need to calculate: 16. Then substitute the given, one line at a time, to get S_∞ =.

    In other words — as if you have never seen this before

    16

    2. What do we already know?

    Copy these onto the left of your page, one per line, with units: 8 · 1/ · 2. Mixing cm with m, or minutes with seconds, loses a method mark.

    3. Which method — and why this one?

    16

    4. Step-by-step working

    1. 01 / 08

      Step A — Read the question twice

      Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.

      Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.

    2. 02 / 08

      Step A2 — Hunt: Given, Missing, Find, Calculate

      Given: Numbers and units already in the sentence: 8 · 1/ · 2. Copy each one into a column. A name without a number is not given. Missing: After you copy the given, the letter that still has no number is missing. The paper is pointing at: S_∞ =. Circle that word — that is the missing variable. Find: We are required to find: S_∞ =. Write that as a symbol on the left, with a question mark, before you touch a formula. Calculate: What we need to calculate: 16. Then substitute the given, one line at a time, to get S_∞ =.

      Why this step: Do not name the letters yet. First hunt: what already has a number (Given), what has no number (Missing), the word the paper wants (Find), and which formula still contains the missing letter (Calculate).

    3. 03 / 08

      Step B — Write the given in a column

      Copy these onto the left of your page, one per line, with units: 8 · 1/ · 2. Mixing cm with m, or minutes with seconds, loses a method mark.

      Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.

    4. 04 / 08

      Step C — Name the method in words

      16

      Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.

    5. 05 / 08

      Working

      |r| < 1 so it converges. S_∞ = a(1 − r) = 8(1/2) = 16. Do not add the first two terms and stop.

      Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.

    6. 06 / 08

      Step G — Sense-check the size

      Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.

      Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.

    7. 07 / 08

      Step F — Box the answer with its unit

      16

      Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.

    8. 08 / 08

      Step H — What the marker is looking for

      On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.

      Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.

    5. The answer

    16

    Copy onto your answer sheet — in this order

    Answer: 16

    6. Check it like a marker

    Does your answer appear as one of the options? Do the units match what was asked (m, N, J, °)? If you put the number back into the original equation, does it still hold? Estimate: is the size sensible?

    7. A trap first-timers fall into

    First-timers often grab the first formula they remember, mix units (cm with m, minutes with seconds), or drop a minus sign. Write the formula in words first: “this equals that, because…”

  17. 17 · 3 Marks

    r=−0.95 means

    Notes: Pearson’s r = −0.95 for a bivariate data set.

    How we got there

    Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.

    Explain in another language · 11

    1. What is the question asking?

    Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: r = −0.95 means

    Before any working — hunt first

    Given

    Numbers and units already in the sentence: 0.95 means. Copy each one into a column. A name without a number is not given.

    Missing

    After you copy the given, the letter that still has no number is missing. The paper is pointing at: 95 means. Circle that word — that is the missing variable.

    Find

    We are required to find: 95 means. Write that as a symbol on the left, with a question mark, before you touch a formula.

    Calculate

    Write |r| = 0.95 with empty letters. Cross out every letter that already has a number. Calculate the letter that is still standing — that gives 95 means.

    In other words — as if you have never seen this before

    r near −1: strong negative linear. r does not prove causation.

    2. What do we already know?

    Pearson’s r = −0.95 for a bivariate data set.

    3. Which method — and why this one?

    r near −1: strong negative linear. r does not prove causation.

    4. Step-by-step working

    1. 01 / 05

      Read the sign

      Negative: as x increases, y tends to decrease.

      Why this step: One job per line so you can find a slip, and so a marker can follow the marks.

    2. 02 / 05

      Read the size

      |r|=0.95 is close to 1, so the linear pattern is strong.

      |r|=0.95

      Why this step: One job per line so you can find a slip, and so a marker can follow the marks.

    3. 03 / 05

      Step G — Sense-check the size

      Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.

      Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.

    4. 04 / 05

      Step F — Box the answer with its unit

      strong negative linear correlation

      Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.

    5. 05 / 05

      Step H — What the marker is looking for

      On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.

      Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.

    5. The answer

    strong negative linear correlation

    Copy onto your answer sheet — in this order

    Formula: |r|=0.95

    Answer: strong negative linear correlation

    6. Check it like a marker

    Scatter would slope down, tightly around a line.

    7. A trap first-timers fall into

    Correlation is not causation. Do not say “x causes y to fall”.

  18. 18 · 2 Marks · Arithmetic & geometric series

    Geometric first term 3, r=2. T₄=

    Formulas

    Tₙ=a rⁿ⁻¹

    Geometric nth term — exponent is n minus 1

    Sₙ=n2 [2a + (n−1)d]

    Arithmetic sum

    Sₙ=a(rⁿ − 1)(r − 1), r ≠ 1

    Geometric sum

    How we got there

    Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.

    Explain in another language · 11

    1. What is the question asking?

    Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: Geometric first term 3, r=2. T₄ =

    Before any working — hunt first

    Given

    Numbers and units already in the sentence: 3 · 2. Copy each one into a column. A name without a number is not given.

    Missing

    After you copy the given, the letter that still has no number is missing. The paper is pointing at: T₄ =. Circle that word — that is the missing variable.

    Find

    We are required to find: T₄ =. Write that as a symbol on the left, with a question mark, before you touch a formula.

    Calculate

    What we need to calculate: T₄ = 3×2³ = 24. Then substitute the given, one line at a time, to get T₄ =.

    In other words — as if you have never seen this before

    T₄=3×2³=24.

    2. What do we already know?

    Copy these onto the left of your page, one per line, with units: 3 · 2. Mixing cm with m, or minutes with seconds, loses a method mark.

    3. Which method — and why this one?

    T₄=3×2³=24.

    4. Step-by-step working

    1. 01 / 08

      Step A — Read the question twice

      Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.

      Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.

    2. 02 / 08

      Step A2 — Hunt: Given, Missing, Find, Calculate

      Given: Numbers and units already in the sentence: 3 · 2. Copy each one into a column. A name without a number is not given. Missing: After you copy the given, the letter that still has no number is missing. The paper is pointing at: T₄ =. Circle that word — that is the missing variable. Find: We are required to find: T₄ =. Write that as a symbol on the left, with a question mark, before you touch a formula. Calculate: What we need to calculate: T₄ = 3×2³ = 24. Then substitute the given, one line at a time, to get T₄ =.

      Why this step: Do not name the letters yet. First hunt: what already has a number (Given), what has no number (Missing), the word the paper wants (Find), and which formula still contains the missing letter (Calculate).

    3. 03 / 08

      Step B — Write the given in a column

      Copy these onto the left of your page, one per line, with units: 3 · 2. Mixing cm with m, or minutes with seconds, loses a method mark.

      Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.

    4. 04 / 08

      Step C — Name the method in words

      T₄=3×2³=24.

      Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.

    5. 05 / 08

      Working

      T₄=3×2³=24.

      Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.

    6. 06 / 08

      Step G — Sense-check the size

      Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.

      Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.

    7. 07 / 08

      Step F — Box the answer with its unit

      24

      Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.

    8. 08 / 08

      Step H — What the marker is looking for

      On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.

      Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.

    5. The answer

    24

    Copy onto your answer sheet — in this order

    Answer: 24

    6. Check it like a marker

    Does your answer appear as one of the options? Do the units match what was asked (m, N, J, °)? If you put the number back into the original equation, does it still hold? Estimate: is the size sensible?

    7. A trap first-timers fall into

    First-timers often grab the first formula they remember, mix units (cm with m, minutes with seconds), or drop a minus sign. Write the formula in words first: “this equals that, because…”

  19. 19 · 4 Marks

    Stationary point of f(x)=x³−3x+1 is at x =

    How we got there

    Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.

    Explain in another language · 11

    1. What is the question asking?

    Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: Stationary point of f(x)=x³−3x+1 is at x =

    In other words — as if you have never seen this before

    f'=3x²−3=0→x²=1→x=±1.

    2. What do we already know?

    Copy these onto the left of your page, one per line, with units: 3x · 1 is. Mixing cm with m, or minutes with seconds, loses a method mark.

    3. Which method — and why this one?

    f'=3x²−3=0→x²=1→x=±1.

    4. Step-by-step working

    1. 01 / 07

      Step A — Read the question twice

      Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.

      Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.

    2. 02 / 07

      Step B — Write the given in a column

      Copy these onto the left of your page, one per line, with units: 3x · 1 is. Mixing cm with m, or minutes with seconds, loses a method mark.

      Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.

    3. 03 / 07

      Step C — Name the method in words

      f'=3x²−3=0→x²=1→x=±1.

      Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.

    4. 04 / 07

      Working

      f'=3x²−3=0→x²=1→x=±1.

      Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.

    5. 05 / 07

      Step G — Sense-check the size

      Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.

      Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.

    6. 06 / 07

      Step F — Box the answer with its unit

      ±1

      Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.

    7. 07 / 07

      Step H — What the marker is looking for

      On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.

      Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.

    5. The answer

    ±1

    Copy onto your answer sheet — in this order

    Answer: ±1

    6. Check it like a marker

    Does your answer appear as one of the options? Do the units match what was asked (m, N, J, °)? If you put the number back into the original equation, does it still hold? Estimate: is the size sensible?

    7. A trap first-timers fall into

    First-timers often grab the first formula they remember, mix units (cm with m, minutes with seconds), or drop a minus sign. Write the formula in words first: “this equals that, because…”

  20. 20 · 3 Marks

    S_∞ of 2 + 4 + 8 + 16 + … is

    How we got there

    Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.

    Explain in another language · 11

    1. What is the question asking?

    Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: S_∞ of 2 + 4 + 8 + 16 + … is

    Before any working — hunt first

    Given

    Numbers and units already in the sentence: 2 · 4 · 8 · 16. Copy each one into a column. A name without a number is not given.

    Missing

    After you copy the given, the letter that still has no number is missing. The paper is pointing at: S_∞ of 2 + 4 + 8 + 16 + … is. Circle that word — that is the missing variable.

    Find

    We are required to find: S_∞ of 2 + 4 + 8 + 16 + … is. Write that as a symbol on the left, with a question mark, before you touch a formula.

    Calculate

    What we need to calculate: r = 2, |r| ≥ 1. Then substitute the given, one line at a time, to get S_∞ of 2 + 4 + 8 + 16 + … is.

    In other words — as if you have never seen this before

    r=2, |r| ≥ 1. Do not write 2(1−2)=−2.

    2. What do we already know?

    Copy these onto the left of your page, one per line, with units: 2 · 4 · 8 · 16. Mixing cm with m, or minutes with seconds, loses a method mark.

    3. Which method — and why this one?

    r=2, |r| ≥ 1. Do not write 2(1−2)=−2.

    4. Step-by-step working

    1. 01 / 08

      Step A — Read the question twice

      Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.

      Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.

    2. 02 / 08

      Step A2 — Hunt: Given, Missing, Find, Calculate

      Given: Numbers and units already in the sentence: 2 · 4 · 8 · 16. Copy each one into a column. A name without a number is not given. Missing: After you copy the given, the letter that still has no number is missing. The paper is pointing at: S_∞ of 2 + 4 + 8 + 16 + … is. Circle that word — that is the missing variable. Find: We are required to find: S_∞ of 2 + 4 + 8 + 16 + … is. Write that as a symbol on the left, with a question mark, before you touch a formula. Calculate: What we need to calculate: r = 2, |r| ≥ 1. Then substitute the given, one line at a time, to get S_∞ of 2 + 4 + 8 + 16 + … is.

      Why this step: Do not name the letters yet. First hunt: what already has a number (Given), what has no number (Missing), the word the paper wants (Find), and which formula still contains the missing letter (Calculate).

    3. 03 / 08

      Step B — Write the given in a column

      Copy these onto the left of your page, one per line, with units: 2 · 4 · 8 · 16. Mixing cm with m, or minutes with seconds, loses a method mark.

      Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.

    4. 04 / 08

      Step C — Name the method in words

      r=2, |r| ≥ 1. Do not write 2(1−2)=−2.

      Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.

    5. 05 / 08

      Working

      r=2, |r| ≥ 1. Do not write 2(1−2)=−2.

      Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.

    6. 06 / 08

      Step G — Sense-check the size

      Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.

      Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.

    7. 07 / 08

      Step F — Box the answer with its unit

      does not exist (diverges)

      Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.

    8. 08 / 08

      Step H — What the marker is looking for

      On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.

      Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.

    5. The answer

    does not exist (diverges)

    Copy onto your answer sheet — in this order

    Answer: does not exist (diverges)

    6. Check it like a marker

    Does your answer appear as one of the options? Do the units match what was asked (m, N, J, °)? If you put the number back into the original equation, does it still hold? Estimate: is the size sensible?

    7. A trap first-timers fall into

    First-timers often grab the first formula they remember, mix units (cm with m, minutes with seconds), or drop a minus sign. Write the formula in words first: “this equals that, because…”

  21. 21 · 2 Marks · First principles of differentiation

    f(x)=x². From first principles f'(x)=

    Formulas

    f'(x)=limh→0[f(x+h) − f(x)]h

    Definition of the derivative

    How we got there

    Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.

    Explain in another language · 11

    1. What is the question asking?

    Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: f(x)=x². From first principles f'(x) =

    Before any working — hunt first

    Given

    Numbers and units already in the sentence: no numbers yet — only a name, a diagram, or a worded unknown. Copy each one into a column. A name without a number is not given.

    Missing

    After you copy the given, the letter that still has no number is missing. The paper is pointing at: From first principles f'(x) =. Circle that word — that is the missing variable.

    Find

    We are required to find: From first principles f'(x) =. Write that as a symbol on the left, with a question mark, before you touch a formula.

    Calculate

    What we need to calculate: [2xh + h²]h. Then substitute the given, one line at a time, to get From first principles f'(x) =.

    In other words — as if you have never seen this before

    [2xh + h²]h→2x as h→0.

    2. What do we already know?

    Copy these onto the left of your page, one per line, with units: every number and its unit in the sentence. Mixing cm with m, or minutes with seconds, loses a method mark.

    3. Which method — and why this one?

    [2xh + h²]h→2x as h→0.

    4. Step-by-step working

    1. 01 / 08

      Step A — Read the question twice

      Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.

      Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.

    2. 02 / 08

      Step A2 — Hunt: Given, Missing, Find, Calculate

      Given: Numbers and units already in the sentence: no numbers yet — only a name, a diagram, or a worded unknown. Copy each one into a column. A name without a number is not given. Missing: After you copy the given, the letter that still has no number is missing. The paper is pointing at: From first principles f'(x) =. Circle that word — that is the missing variable. Find: We are required to find: From first principles f'(x) =. Write that as a symbol on the left, with a question mark, before you touch a formula. Calculate: What we need to calculate: [2xh + h²]h. Then substitute the given, one line at a time, to get From first principles f'(x) =.

      Why this step: Do not name the letters yet. First hunt: what already has a number (Given), what has no number (Missing), the word the paper wants (Find), and which formula still contains the missing letter (Calculate).

    3. 03 / 08

      Step B — Write the given in a column

      Copy these onto the left of your page, one per line, with units: every number and its unit in the sentence. Mixing cm with m, or minutes with seconds, loses a method mark.

      Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.

    4. 04 / 08

      Step C — Name the method in words

      [2xh + h²]h→2x as h→0.

      Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.

    5. 05 / 08

      Working

      [2xh + h²]h→2x as h→0.

      Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.

    6. 06 / 08

      Step G — Sense-check the size

      Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.

      Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.

    7. 07 / 08

      Step F — Box the answer with its unit

      2x

      Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.

    8. 08 / 08

      Step H — What the marker is looking for

      On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.

      Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.

    5. The answer

    2x

    Copy onto your answer sheet — in this order

    Answer: 2x

    6. Check it like a marker

    Does your answer appear as one of the options? Do the units match what was asked (m, N, J, °)? If you put the number back into the original equation, does it still hold? Estimate: is the size sensible?

    7. A trap first-timers fall into

    First-timers often grab the first formula they remember, mix units (cm with m, minutes with seconds), or drop a minus sign. Write the formula in words first: “this equals that, because…”

  22. 22 · 2 Marks · First principles of differentiation

    The definition of f'(x) uses

    Formulas

    f'(x)=limh→0[f(x+h) − f(x)]h

    Definition of the derivative

    How we got there

    Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.

    Explain in another language · 11

    1. What is the question asking?

    Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: The definition of f'(x) uses

    Before any working — hunt first

    Given

    Numbers and units already in the sentence: no numbers yet — only a name, a diagram, or a worded unknown. Copy each one into a column. A name without a number is not given.

    Missing

    After you copy the given, the letter that still has no number is missing. The paper is pointing at: The definition of f'(x) uses. Circle that word — that is the missing variable.

    Find

    We are required to find: The definition of f'(x) uses. Write that as a symbol on the left, with a question mark, before you touch a formula.

    Calculate

    What we need to calculate: First principles. Then substitute the given, one line at a time, to get The definition of f'(x) uses.

    In other words — as if you have never seen this before

    First principles.

    2. What do we already know?

    Copy these onto the left of your page, one per line, with units: every number and its unit in the sentence. Mixing cm with m, or minutes with seconds, loses a method mark.

    3. Which method — and why this one?

    First principles.

    4. Step-by-step working

    1. 01 / 08

      Step A — Read the question twice

      Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.

      Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.

    2. 02 / 08

      Step A2 — Hunt: Given, Missing, Find, Calculate

      Given: Numbers and units already in the sentence: no numbers yet — only a name, a diagram, or a worded unknown. Copy each one into a column. A name without a number is not given. Missing: After you copy the given, the letter that still has no number is missing. The paper is pointing at: The definition of f'(x) uses. Circle that word — that is the missing variable. Find: We are required to find: The definition of f'(x) uses. Write that as a symbol on the left, with a question mark, before you touch a formula. Calculate: What we need to calculate: First principles. Then substitute the given, one line at a time, to get The definition of f'(x) uses.

      Why this step: Do not name the letters yet. First hunt: what already has a number (Given), what has no number (Missing), the word the paper wants (Find), and which formula still contains the missing letter (Calculate).

    3. 03 / 08

      Step B — Write the given in a column

      Copy these onto the left of your page, one per line, with units: every number and its unit in the sentence. Mixing cm with m, or minutes with seconds, loses a method mark.

      Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.

    4. 04 / 08

      Step C — Name the method in words

      First principles.

      Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.

    5. 05 / 08

      Working

      First principles.

      Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.

    6. 06 / 08

      Step G — Sense-check the size

      Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.

      Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.

    7. 07 / 08

      Step F — Box the answer with its unit

      limh→0[f(x+h)−f(x)]h

      Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.

    8. 08 / 08

      Step H — What the marker is looking for

      On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.

      Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.

    5. The answer

    limh→0[f(x+h)−f(x)]h

    Copy onto your answer sheet — in this order

    Answer: limh→0 [f(x+h)−f(x)]h

    6. Check it like a marker

    Does your answer appear as one of the options? Do the units match what was asked (m, N, J, °)? If you put the number back into the original equation, does it still hold? Estimate: is the size sensible?

    7. A trap first-timers fall into

    First-timers often grab the first formula they remember, mix units (cm with m, minutes with seconds), or drop a minus sign. Write the formula in words first: “this equals that, because…”

  23. 23 · 2 Marks · Area, sine and cosine rules

    ddx (4x⁵)=

    Formulas

    Area=½ ab sin C

    Area rule

    c²=a²+b²−2ab cos C

    Cosine rule

    Notes: f(x) = 4x⁵. Unknown: the derivative f'(x).

    How we got there

    Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.

    Explain in another language · 11

    1. What is the question asking?

    Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: ddx (4x⁵) =

    Before any working — hunt first

    Given

    Numbers and units already in the sentence: 4x. Copy each one into a column. A name without a number is not given.

    Missing

    After you copy the given, the letter that still has no number is missing. The paper is pointing at: ddx (4x⁵) =. Circle that word — that is the missing variable.

    Find

    We are required to find: ddx (4x⁵) =. Write that as a symbol on the left, with a question mark, before you touch a formula.

    Calculate

    Write ddx [k xⁿ] = k n xⁿ⁻¹ with empty letters. Cross out every letter that already has a number. Calculate the letter that is still standing — that gives ddx (4x⁵) =.

    In other words — as if you have never seen this before

    Power rule in words: bring the index down to multiply, then drop the index by one.

    2. What do we already know?

    f(x) = 4x⁵. Unknown: the derivative f'(x).

    3. Which method — and why this one?

    Power rule in words: bring the index down to multiply, then drop the index by one.

    4. Step-by-step working

    1. 01 / 08

      Step A — Read the question twice

      Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.

      Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.

    2. 02 / 08

      Step A2 — Hunt: Given, Missing, Find, Calculate

      Given: Numbers and units already in the sentence: 4x. Copy each one into a column. A name without a number is not given. Missing: After you copy the given, the letter that still has no number is missing. The paper is pointing at: ddx (4x⁵) =. Circle that word — that is the missing variable. Find: We are required to find: ddx (4x⁵) =. Write that as a symbol on the left, with a question mark, before you touch a formula. Calculate: Write ddx [k xⁿ] = k n xⁿ⁻¹ with empty letters. Cross out every letter that already has a number. Calculate the letter that is still standing — that gives ddx (4x⁵) =.

      Why this step: Do not name the letters yet. First hunt: what already has a number (Given), what has no number (Missing), the word the paper wants (Find), and which formula still contains the missing letter (Calculate).

    3. 03 / 08

      Step B — Write the given in a column

      f(x) = 4x⁵. Unknown: the derivative f'(x).

      Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.

    4. 04 / 08

      Step C — Name the method in words

      Power rule in words: bring the index down to multiply, then drop the index by one.

      Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.

    5. 05 / 08

      Bring the 5 down

      5 × 4 = 20, and the index becomes 4. So 20x⁴.

      ddx [k xⁿ]=k n xⁿ⁻¹

      Why this step: The 4 is a constant multiplier — it just tags along. You do not drop it, and you do not add it to 5.

    6. 06 / 08

      Step G — Sense-check the size

      Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.

      Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.

    7. 07 / 08

      Step F — Box the answer with its unit

      20x⁴

      Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.

    8. 08 / 08

      Step H — What the marker is looking for

      On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.

      Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.

    5. The answer

    20x⁴

    Copy onto your answer sheet — in this order

    Formula: ddx [k xⁿ]=k n xⁿ⁻¹

    Answer: 20x⁴

    6. Check it like a marker

    At x = 1, slope should be 20. A 4x⁵ curve is steep there. 4x⁴ would be four times too gentle.

    7. A trap first-timers fall into

    Writing 4x⁴ (forgot to multiply by 5) or x⁶ (that is integration, the reverse road).

  24. 24 · 2 Marks · Compound angles

    sin 15° in surd form uses

    hbθ

    Formulas

    sin(A + B)=sin A cos B+cos A sin B

    Sine compound

    How we got there

    Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.

    Explain in another language · 11

    1. What is the question asking?

    Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: sin 15° in surd form uses

    Before any working — hunt first

    Given

    Numbers and units already in the sentence: 15°. Copy each one into a column. A name without a number is not given.

    Missing

    After you copy the given, the letter that still has no number is missing. The paper is pointing at: sin 15° in surd form uses. Circle that word — that is the missing variable.

    Find

    We are required to find: sin 15° in surd form uses. Write that as a symbol on the left, with a question mark, before you touch a formula.

    Calculate

    What we need to calculate: sin(45−30). Then substitute the given, one line at a time, to get sin 15° in surd form uses.

    In other words — as if you have never seen this before

    sin(45−30)

    2. What do we already know?

    Copy these onto the left of your page, one per line, with units: 15°. Mixing cm with m, or minutes with seconds, loses a method mark.

    3. Which method — and why this one?

    sin(45−30)

    4. Step-by-step working

    1. 01 / 08

      Step A — Read the question twice

      Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.

      Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.

    2. 02 / 08

      Step A2 — Hunt: Given, Missing, Find, Calculate

      Given: Numbers and units already in the sentence: 15°. Copy each one into a column. A name without a number is not given. Missing: After you copy the given, the letter that still has no number is missing. The paper is pointing at: sin 15° in surd form uses. Circle that word — that is the missing variable. Find: We are required to find: sin 15° in surd form uses. Write that as a symbol on the left, with a question mark, before you touch a formula. Calculate: What we need to calculate: sin(45−30). Then substitute the given, one line at a time, to get sin 15° in surd form uses.

      Why this step: Do not name the letters yet. First hunt: what already has a number (Given), what has no number (Missing), the word the paper wants (Find), and which formula still contains the missing letter (Calculate).

    3. 03 / 08

      Step B — Write the given in a column

      Copy these onto the left of your page, one per line, with units: 15°. Mixing cm with m, or minutes with seconds, loses a method mark.

      Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.

    4. 04 / 08

      Step C — Name the method in words

      sin(45−30)

      Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.

    5. 05 / 08

      Reason

      Compound angle.

      Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.

    6. 06 / 08

      Step G — Sense-check the size

      Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.

      Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.

    7. 07 / 08

      Step F — Box the answer with its unit

      sin(45−30)

      Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.

    8. 08 / 08

      Step H — What the marker is looking for

      On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.

      Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.

    5. The answer

    sin(45−30)

    Copy onto your answer sheet — in this order

    Answer: sin(45−30)

    6. Check it like a marker

    Does your answer appear as one of the options? Do the units match what was asked (m, N, J, °)? If you put the number back into the original equation, does it still hold? Estimate: is the size sensible?

    7. A trap first-timers fall into

    First-timers often grab the first formula they remember, mix units (cm with m, minutes with seconds), or drop a minus sign. Write the formula in words first: “this equals that, because…”

  25. 25 · 2 Marks · Area, sine and cosine rules

    ddx (x³)=

    Formulas

    Area=½ ab sin C

    Area rule

    c²=a²+b²−2ab cos C

    Cosine rule

    How we got there

    Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.

    Explain in another language · 11

    1. What is the question asking?

    Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: ddx (x³) =

    Before any working — hunt first

    Given

    Numbers and units already in the sentence: no numbers yet — only a name, a diagram, or a worded unknown. Copy each one into a column. A name without a number is not given.

    Missing

    After you copy the given, the letter that still has no number is missing. The paper is pointing at: ddx (x³) =. Circle that word — that is the missing variable.

    Find

    We are required to find: ddx (x³) =. Write that as a symbol on the left, with a question mark, before you touch a formula.

    Calculate

    What we need to calculate: Power rule: n x^{n−1}. Then substitute the given, one line at a time, to get ddx (x³) =.

    In other words — as if you have never seen this before

    Power rule: n xⁿ⁻¹.

    2. What do we already know?

    Copy these onto the left of your page, one per line, with units: every number and its unit in the sentence. Mixing cm with m, or minutes with seconds, loses a method mark.

    3. Which method — and why this one?

    Power rule: n xⁿ⁻¹.

    4. Step-by-step working

    1. 01 / 08

      Step A — Read the question twice

      Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.

      Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.

    2. 02 / 08

      Step A2 — Hunt: Given, Missing, Find, Calculate

      Given: Numbers and units already in the sentence: no numbers yet — only a name, a diagram, or a worded unknown. Copy each one into a column. A name without a number is not given. Missing: After you copy the given, the letter that still has no number is missing. The paper is pointing at: ddx (x³) =. Circle that word — that is the missing variable. Find: We are required to find: ddx (x³) =. Write that as a symbol on the left, with a question mark, before you touch a formula. Calculate: What we need to calculate: Power rule: n x^{n−1}. Then substitute the given, one line at a time, to get ddx (x³) =.

      Why this step: Do not name the letters yet. First hunt: what already has a number (Given), what has no number (Missing), the word the paper wants (Find), and which formula still contains the missing letter (Calculate).

    3. 03 / 08

      Step B — Write the given in a column

      Copy these onto the left of your page, one per line, with units: every number and its unit in the sentence. Mixing cm with m, or minutes with seconds, loses a method mark.

      Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.

    4. 04 / 08

      Step C — Name the method in words

      Power rule: n xⁿ⁻¹.

      Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.

    5. 05 / 08

      Working

      Power rule: n xⁿ⁻¹.

      Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.

    6. 06 / 08

      Step G — Sense-check the size

      Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.

      Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.

    7. 07 / 08

      Step F — Box the answer with its unit

      3x²

      Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.

    8. 08 / 08

      Step H — What the marker is looking for

      On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.

      Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.

    5. The answer

    3x²

    Copy onto your answer sheet — in this order

    Answer: 3x²

    6. Check it like a marker

    Does your answer appear as one of the options? Do the units match what was asked (m, N, J, °)? If you put the number back into the original equation, does it still hold? Estimate: is the size sensible?

    7. A trap first-timers fall into

    First-timers often grab the first formula they remember, mix units (cm with m, minutes with seconds), or drop a minus sign. Write the formula in words first: “this equals that, because…”

  26. 26 · 4 Marks

    Predicting y outside the given x-range is

    How we got there

    Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.

    Explain in another language · 11

    1. What is the question asking?

    Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: Predicting y outside the given x-range is

    In other words — as if you have never seen this before

    Outside the data cloud.

    2. What do we already know?

    Copy these onto the left of your page, one per line, with units: every number and its unit in the sentence. Mixing cm with m, or minutes with seconds, loses a method mark.

    3. Which method — and why this one?

    Outside the data cloud.

    4. Step-by-step working

    1. 01 / 07

      Step A — Read the question twice

      Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.

      Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.

    2. 02 / 07

      Step B — Write the given in a column

      Copy these onto the left of your page, one per line, with units: every number and its unit in the sentence. Mixing cm with m, or minutes with seconds, loses a method mark.

      Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.

    3. 03 / 07

      Step C — Name the method in words

      Outside the data cloud.

      Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.

    4. 04 / 07

      Working

      Outside the data cloud.

      Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.

    5. 05 / 07

      Step G — Sense-check the size

      Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.

      Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.

    6. 06 / 07

      Step F — Box the answer with its unit

      extrapolation

      Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.

    7. 07 / 07

      Step H — What the marker is looking for

      On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.

      Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.

    5. The answer

    extrapolation

    Copy onto your answer sheet — in this order

    Answer: extrapolation

    6. Check it like a marker

    Does your answer appear as one of the options? Do the units match what was asked (m, N, J, °)? If you put the number back into the original equation, does it still hold? Estimate: is the size sensible?

    7. A trap first-timers fall into

    First-timers often grab the first formula they remember, mix units (cm with m, minutes with seconds), or drop a minus sign. Write the formula in words first: “this equals that, because…”

  27. 27 · 3 Marks

    log₂ 32=

    How we got there

    Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.

    Explain in another language · 11

    1. What is the question asking?

    Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: log₂ 32 =

    Before any working — hunt first

    Given

    Numbers and units already in the sentence: 32. Copy each one into a column. A name without a number is not given.

    Missing

    After you copy the given, the letter that still has no number is missing. The paper is pointing at: log₂ 32 =. Circle that word — that is the missing variable.

    Find

    We are required to find: log₂ 32 =. Write that as a symbol on the left, with a question mark, before you touch a formula.

    Calculate

    What we need to calculate: 5. Then substitute the given, one line at a time, to get log₂ 32 =.

    In other words — as if you have never seen this before

    5

    2. What do we already know?

    Copy these onto the left of your page, one per line, with units: 32. Mixing cm with m, or minutes with seconds, loses a method mark.

    3. Which method — and why this one?

    5

    4. Step-by-step working

    1. 01 / 08

      Step A — Read the question twice

      Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.

      Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.

    2. 02 / 08

      Step A2 — Hunt: Given, Missing, Find, Calculate

      Given: Numbers and units already in the sentence: 32. Copy each one into a column. A name without a number is not given. Missing: After you copy the given, the letter that still has no number is missing. The paper is pointing at: log₂ 32 =. Circle that word — that is the missing variable. Find: We are required to find: log₂ 32 =. Write that as a symbol on the left, with a question mark, before you touch a formula. Calculate: What we need to calculate: 5. Then substitute the given, one line at a time, to get log₂ 32 =.

      Why this step: Do not name the letters yet. First hunt: what already has a number (Given), what has no number (Missing), the word the paper wants (Find), and which formula still contains the missing letter (Calculate).

    3. 03 / 08

      Step B — Write the given in a column

      Copy these onto the left of your page, one per line, with units: 32. Mixing cm with m, or minutes with seconds, loses a method mark.

      Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.

    4. 04 / 08

      Step C — Name the method in words

      5

      Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.

    5. 05 / 08

      Reason

      2⁵=32.

      Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.

    6. 06 / 08

      Step G — Sense-check the size

      Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.

      Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.

    7. 07 / 08

      Step F — Box the answer with its unit

      5

      Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.

    8. 08 / 08

      Step H — What the marker is looking for

      On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.

      Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.

    5. The answer

    5

    Copy onto your answer sheet — in this order

    Answer: 5

    6. Check it like a marker

    Does your answer appear as one of the options? Do the units match what was asked (m, N, J, °)? If you put the number back into the original equation, does it still hold? Estimate: is the size sensible?

    7. A trap first-timers fall into

    First-timers often grab the first formula they remember, mix units (cm with m, minutes with seconds), or drop a minus sign. Write the formula in words first: “this equals that, because…”

  28. 28 · 2 Marks

    5P2=

    How we got there

    Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.

    Explain in another language · 11

    1. What is the question asking?

    Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: 5P2 =

    Before any working — hunt first

    Given

    Numbers and units already in the sentence: 5P · 2. Copy each one into a column. A name without a number is not given.

    Missing

    After you copy the given, the letter that still has no number is missing. The paper is pointing at: 5P2 =. Circle that word — that is the missing variable.

    Find

    We are required to find: 5P2 =. Write that as a symbol on the left, with a question mark, before you touch a formula.

    Calculate

    What we need to calculate: 5×4 = 20. Then substitute the given, one line at a time, to get 5P2 =.

    In other words — as if you have never seen this before

    5×4=20.

    2. What do we already know?

    Copy these onto the left of your page, one per line, with units: 5P · 2. Mixing cm with m, or minutes with seconds, loses a method mark.

    3. Which method — and why this one?

    5×4=20.

    4. Step-by-step working

    1. 01 / 08

      Step A — Read the question twice

      Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.

      Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.

    2. 02 / 08

      Step A2 — Hunt: Given, Missing, Find, Calculate

      Given: Numbers and units already in the sentence: 5P · 2. Copy each one into a column. A name without a number is not given. Missing: After you copy the given, the letter that still has no number is missing. The paper is pointing at: 5P2 =. Circle that word — that is the missing variable. Find: We are required to find: 5P2 =. Write that as a symbol on the left, with a question mark, before you touch a formula. Calculate: What we need to calculate: 5×4 = 20. Then substitute the given, one line at a time, to get 5P2 =.

      Why this step: Do not name the letters yet. First hunt: what already has a number (Given), what has no number (Missing), the word the paper wants (Find), and which formula still contains the missing letter (Calculate).

    3. 03 / 08

      Step B — Write the given in a column

      Copy these onto the left of your page, one per line, with units: 5P · 2. Mixing cm with m, or minutes with seconds, loses a method mark.

      Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.

    4. 04 / 08

      Step C — Name the method in words

      5×4=20.

      Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.

    5. 05 / 08

      Working

      5×4=20.

      Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.

    6. 06 / 08

      Step G — Sense-check the size

      Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.

      Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.

    7. 07 / 08

      Step F — Box the answer with its unit

      20

      Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.

    8. 08 / 08

      Step H — What the marker is looking for

      On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.

      Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.

    5. The answer

    20

    Copy onto your answer sheet — in this order

    Answer: 20

    6. Check it like a marker

    Does your answer appear as one of the options? Do the units match what was asked (m, N, J, °)? If you put the number back into the original equation, does it still hold? Estimate: is the size sensible?

    7. A trap first-timers fall into

    First-timers often grab the first formula they remember, mix units (cm with m, minutes with seconds), or drop a minus sign. Write the formula in words first: “this equals that, because…”

  29. 29 · 3 Marks

    Angle of elevation is measured from the

    How we got there

    Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.

    Explain in another language · 11

    1. What is the question asking?

    Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: Angle of elevation is measured from the

    Before any working — hunt first

    Given

    Numbers and units already in the sentence: no numbers yet — only a name, a diagram, or a worded unknown. Copy each one into a column. A name without a number is not given.

    Missing

    After you copy the given, the letter that still has no number is missing. The paper is pointing at: Angle of elevation is measured from the. Circle that word — that is the missing variable.

    Find

    We are required to find: Angle of elevation is measured from the. Write that as a symbol on the left, with a question mark, before you touch a formula.

    Calculate

    What we need to calculate: Elevation from horizontal. Then substitute the given, one line at a time, to get Angle of elevation is measured from the.

    In other words — as if you have never seen this before

    Elevation from horizontal.

    2. What do we already know?

    Copy these onto the left of your page, one per line, with units: every number and its unit in the sentence. Mixing cm with m, or minutes with seconds, loses a method mark.

    3. Which method — and why this one?

    Elevation from horizontal.

    4. Step-by-step working

    1. 01 / 08

      Step A — Read the question twice

      Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.

      Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.

    2. 02 / 08

      Step A2 — Hunt: Given, Missing, Find, Calculate

      Given: Numbers and units already in the sentence: no numbers yet — only a name, a diagram, or a worded unknown. Copy each one into a column. A name without a number is not given. Missing: After you copy the given, the letter that still has no number is missing. The paper is pointing at: Angle of elevation is measured from the. Circle that word — that is the missing variable. Find: We are required to find: Angle of elevation is measured from the. Write that as a symbol on the left, with a question mark, before you touch a formula. Calculate: What we need to calculate: Elevation from horizontal. Then substitute the given, one line at a time, to get Angle of elevation is measured from the.

      Why this step: Do not name the letters yet. First hunt: what already has a number (Given), what has no number (Missing), the word the paper wants (Find), and which formula still contains the missing letter (Calculate).

    3. 03 / 08

      Step B — Write the given in a column

      Copy these onto the left of your page, one per line, with units: every number and its unit in the sentence. Mixing cm with m, or minutes with seconds, loses a method mark.

      Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.

    4. 04 / 08

      Step C — Name the method in words

      Elevation from horizontal.

      Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.

    5. 05 / 08

      Working

      Elevation from horizontal.

      Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.

    6. 06 / 08

      Step G — Sense-check the size

      Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.

      Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.

    7. 07 / 08

      Step F — Box the answer with its unit

      horizontal up to the line of sight

      Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.

    8. 08 / 08

      Step H — What the marker is looking for

      On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.

      Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.

    5. The answer

    horizontal up to the line of sight

    Copy onto your answer sheet — in this order

    Answer: horizontal up to the line of sight

    6. Check it like a marker

    Does your answer appear as one of the options? Do the units match what was asked (m, N, J, °)? If you put the number back into the original equation, does it still hold? Estimate: is the size sensible?

    7. A trap first-timers fall into

    First-timers often grab the first formula they remember, mix units (cm with m, minutes with seconds), or drop a minus sign. Write the formula in words first: “this equals that, because…”

  30. 30 · 4 Marks

    log₅ 125=

    Notes: log₅ 125. In words: “5 to the what equals 125?”

    How we got there

    Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.

    Explain in another language · 11

    1. What is the question asking?

    Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: log₅ 125 =

    Before any working — hunt first

    Given

    Numbers and units already in the sentence: 125. Copy each one into a column. A name without a number is not given.

    Missing

    After you copy the given, the letter that still has no number is missing. The paper is pointing at: log₅ 125 =. Circle that word — that is the missing variable.

    Find

    We are required to find: log₅ 125 =. Write that as a symbol on the left, with a question mark, before you touch a formula.

    Calculate

    Write 5ˣ = 125 with empty letters. Cross out every letter that already has a number. Calculate the letter that is still standing — that gives log₅ 125 =.

    In other words — as if you have never seen this before

    A logarithm is an index. Convert to 5ˣ = 125, then notice 5³ = 125.

    2. What do we already know?

    log₅ 125. In words: “5 to the what equals 125?”

    3. Which method — and why this one?

    A logarithm is an index. Convert to 5ˣ = 125, then notice 5³ = 125.

    4. Step-by-step working

    1. 01 / 05

      Rewrite as an exponential

      log₅ 125=x⇔5ˣ=125.

      5ˣ=125

      Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.

    2. 02 / 05

      Recognise the power

      5¹=5, 5²=25, 5³=125. So x=3.

      x=3

      Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.

    3. 03 / 05

      Step G — Sense-check the size

      Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.

      Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.

    4. 04 / 05

      Step F — Box the answer with its unit

      3

      Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.

    5. 05 / 05

      Step H — What the marker is looking for

      On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.

      Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.

    5. The answer

    3

    Copy onto your answer sheet — in this order

    Formula: 5ˣ=125

    Answer: 3

    6. Check it like a marker

    5³=5×5×5=125. Yes.

    7. A trap first-timers fall into

    Writing 25 (that is 1255) or 5 (the base). A log is not a divide.

Ntsako · fx-991ZA PLUS. Tap to calculate.