Keystones — Capstone
Five GCSE retrieval questions · 17 September 2026 · mathsvault.uk/keystones
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1. Number Rationalising the denominator
Rationalise: 3/√2
Answer: 3√2⁄2 -
2. Algebra Factorising non-monic quadratics
Factorise: 4x² + 2x - 20
Answer: (2x - 4)(2x + 5) -
3. Geometry SOHCAHTOA — missing length
Adjacent = 30cm, angle = 59°. Find opposite
Answer: 49.9cm -
4. Ratio Reverse percentages
A price of £348.44 includes a 24% increase. What was the price before the increase?
Answer: £281.00 -
5. Statistics Mean
The mean of 4 numbers is 24. If 3 of them are 46, 19, 33, what is the missing number?
Answer: -2