Keystones — Capstone
Five GCSE retrieval questions · 16 September 2026 · mathsvault.uk/keystones
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1. Number Rationalising the denominator
Rationalise: 3/√3
Answer: 3√3⁄3 -
2. Algebra Factorising non-monic quadratics
Factorise: 12x² + 11x - 15
Answer: (4x - 3)(3x + 5) -
3. Geometry SOHCAHTOA — missing length
Adjacent = 19cm, angle = 50°. Find opposite
Answer: 22.6cm -
4. Ratio Reverse percentages
A price of £242.76 includes a 19% increase. What was the price before the increase?
Answer: £204.00 -
5. Statistics Mean
The mean of 5 numbers is 40. If 4 of them are 39, 26, 34, 40, what is the missing number?
Answer: 61