Keystones — Capstone
Five GCSE retrieval questions · 3 November 2026 · mathsvault.uk/keystones
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1. Number Rationalising the denominator
Rationalise: 3/√5
Answer: 3√5⁄5 -
2. Algebra Factorising non-monic quadratics
Factorise: 8x² -12x - 20
Answer: (2x - 5)(4x + 4) -
3. Geometry SOHCAHTOA — missing length
Adjacent = 15cm, angle = 55°. Find opposite
Answer: 21.4cm -
4. Ratio Reverse percentages
A price of £686.25 includes a 25% increase. What was the price before the increase?
Answer: £549.00 -
5. Statistics Mean
The mean of 4 numbers is 22. If 3 of them are 25, 46, 43, what is the missing number?
Answer: -26