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S1 Maths Directed Numbers and Algebra Paper 4: Error Review
S1 Maths Directed Numbers and Algebra Paper 4: Error Review
Ten original error-review items, each with an answer and a one-line explanation.
Direct answers Items 1-3 revisit mixed-sign addition and double negatives, 4-6 cover division signs, like terms and brackets, 7-9 substitute negative values and solve equations, and item 10 separates −2² from (−2)². Cover the answers first, then check each note.
01 Paper details (check answers afterwards)
| Item | Detail |
|---|---|
| Questions | 10 |
| Suggested time | 20 |
| Difficulty mix | Foundation 3 · Intermediate 3 · Challenge 3 · Error redo 1 |
| Chapter | Chapter: S1 Maths Directed Numbers and Algebra |
| Level | S1 |
02 Questions (10 items)
- FoundationError review: (−7) + 3 = ?
- FoundationError review: (−5) − (−8) = ?
- FoundationError review: (−4) × (−6) = ?
- IntermediateError review: (−36) ÷ 9 = ?
- IntermediateError review: simplify 3a − 5a.
- IntermediateError review: expand and simplify 2(x − 3) + 4.
- ChallengeError review: find x² − 3x when x = −2.
- ChallengeError review: solve 2x + 7 = 1.
- ChallengeError review: solve 5 − 3x = −7.
- Error redoError review: a pupil says −2² = 4 because negatives cancel. What is the correct value?
03 Answers and one-line notes
| # | Answer | One-line note |
|---|---|---|
| 1 | -4 | With opposite signs keep the sign of the larger size: 7 − 3 = 4, so −4; −10 comes from adding the sizes. |
| 2 | 3 | Subtracting a negative adds: −5 + 8 = 3; −13 ignores the double sign. |
| 3 | 24 | A negative times a negative is positive, 4 x 6 = 24; −24 drops the sign rule. |
| 4 | -4 | Dividing with opposite signs gives a negative: 36 / 9 = 4, so -4; 4 misses the sign. |
| 5 | −2a | Subtract the numbers in front: 3 − 5 = −2, giving −2a; 2a reverses the order. |
| 6 | 2x − 2 | 2x − 6 + 4 = 2x − 2; multiplying only the x gives 2x + 1. |
| 7 | 10 | Square first: (−2)² = 4, then subtract 3 x (−2) = −6, giving 10; −10 misses the sign change. |
| 8 | x = -3 | 2x = 1 − 7 = −6, so x = -3; x = 4 subtracts the wrong way. |
| 9 | x = 4 | −3x = −7 − 5 = −12, so x = 4; skipping the sign change gives −4. |
| 10 | -4, since the square is taken first | −2² means −(2 x 2) = -4; only (−2)² equals 4, and the brackets make the difference. |
04 What to do after marking
- After marking, redo only the wrong items and write down which step went wrong (formula, unit, or misread number).
- Repeat the same item two days later; move to the next paper only when both attempts are correct.
- Parents only need the answer and note columns; there is no need to explain every item.
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Questions and answers are written originally by the TutorZone team and are not taken from any school, publisher or examination authority paper. Every value is checked by computer.