Keystones — Capstone
Five GCSE retrieval questions · 6 January 2026 · mathsvault.uk/keystones
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1. Number Error intervals
56 is rounded to the nearest integer. What is the error interval?
Answer: 55.5 ≤ x < 56.5 -
2. Algebra Linear simultaneous equations
Solve: 2x + 3y = 15 and 3x - y = 6
Answer: x = 3, y = 3 -
3. Geometry Distance between two points
Find the distance between (-4, -2) and (3, 7)
Answer: 11.4 -
4. Ratio Repeated percentage change
A car worth £8,743.00 depreciates by 10% each year for 5 years. What is it worth after 5 years?
Answer: £5,162.65 -
5. Statistics Expected frequency
A bag has 2 red out of 10 balls. If you pick 116 times (with replacement), how many times would you expect red?
Answer: 23.2