4024_s26_ms_13 — 2026 May-June Mathematics D 4024 Mark Scheme 1 Variant 3 · Cambridge CAIE O Level

Expressions treated as equations — adding '=0' to solve an expression

“Some candidates treated algebraic expressions as equations, inappropriately setting them equal to zero or attempting to 'solve' when the question asked to simplify or factorise.”— 4024 Paper 1, May/June 2023

How to fix: An expression has no equals sign — you can only simplify or factorise it. An equation HAS an equals sign — you can solve it. If the question says 'simplify' or 'factorise', do NOT add '= 0'. Read the command word carefully before starting.

Standard form arithmetic errors — subtracting numbers before adjusting powers

“Candidates made errors in standard form calculations by attempting to add or subtract numbers in standard form without first converting them to the same power of 10.”— 4024 Paper 1, May/June 2023

How to fix: Before adding or subtracting numbers in standard form, convert them to the SAME power of 10. For example: 3.2 × 10⁴ + 5.1 × 10³ → 32 × 10³ + 5.1 × 10³ = 37.1 × 10³ = 3.71 × 10⁴. For multiplication and division, you can work with the powers separately.

Inequality sign not reversed when dividing by negative

“A persistent error was failing to reverse the inequality sign when multiplying or dividing both sides by a negative number.”— 4024 Paper 1, May/June 2023

How to fix: When you multiply or divide both sides of an inequality by a NEGATIVE number, you MUST flip the inequality sign. For example: -2x > 6 → divide by -2 → x < -3 (sign flips). If you forget to flip, your answer will be the opposite of the correct range. Tip: substitute a value to check your answer makes sense.