Keystones — Capstone
Five GCSE retrieval questions · 26 April 2026 · mathsvault.uk/keystones
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1. Number Rationalising the denominator
Rationalise the denominator: 6/√12
Answer: √3 (or 3√3⁄3) -
2. Algebra Factorising non-monic quadratics
Factorise: 12x² + 2x - 4
Answer: (4x - 2)(3x + 2) -
3. Geometry SOHCAHTOA — missing length
Adjacent = 25cm, angle = 58°. Find opposite
Answer: 40cm -
4. Ratio Reverse percentages
A price of £659.68 includes a 33% increase. What was the price before the increase?
Answer: £496.00 -
5. Statistics Mean
The mean of 4 numbers is 40. If 3 of them are 27, 26, 27, what is the missing number?
Answer: 80