Keystones — Capstone
Five GCSE retrieval questions · 13 June 2026 · mathsvault.uk/keystones
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1. Number Rationalising the denominator
Rationalise: 5/√2
Answer: 5√2⁄2 -
2. Algebra Factorising non-monic quadratics
Factorise: 4x² -4x - 8
Answer: (2x - 4)(2x + 2) -
3. Geometry SOHCAHTOA — missing length
Adjacent = 13cm, angle = 40°. Find opposite
Answer: 10.9cm -
4. Ratio Reverse percentages
A price of £844.95 includes a 31% increase. What was the price before the increase?
Answer: £645.00 -
5. Statistics Mean
The mean of 5 numbers is 23. If 4 of them are 15, 22, 37, 50, what is the missing number?
Answer: -9