Keystones — Capstone
Five GCSE retrieval questions · 14 September 2026 · mathsvault.uk/keystones
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1. Number Rationalising the denominator
Rationalise: 2/√2
Answer: 2√2⁄2 -
2. Algebra Factorising non-monic quadratics
Factorise: 12x² + x - 20
Answer: (4x - 5)(3x + 4) -
3. Geometry SOHCAHTOA — missing length
Adjacent = 13cm, angle = 36°. Find opposite
Answer: 9.4cm -
4. Ratio Reverse percentages
A price of £492.66 includes a 26% increase. What was the price before the increase?
Answer: £391.00 -
5. Statistics Mean
The mean of 4 numbers is 38. If 3 of them are 18, 16, 24, what is the missing number?
Answer: 94