Keystones — Capstone
Five GCSE retrieval questions · 27 July 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: 16x² -12x - 10
Answer: (4x - 5)(4x + 2) -
3. Geometry SOHCAHTOA — missing length
Adjacent = 14cm, angle = 57°. Find opposite
Answer: 21.6cm -
4. Ratio Reverse percentages
A price of £258.30 includes a 26% increase. What was the price before the increase?
Answer: £205.00 -
5. Statistics Mean
The mean of 6 numbers is 39. If 5 of them are 16, 22, 40, 36, 49, what is the missing number?
Answer: 71