Keystones — Capstone
Five GCSE retrieval questions · 5 March 2026 · mathsvault.uk/keystones
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1. Number Rationalising the denominator
Rationalise: 6/√2
Answer: 6√2⁄2 -
2. Algebra Factorising non-monic quadratics
Factorise: 6x² + 9x - 15
Answer: (3x - 3)(2x + 5) -
3. Geometry SOHCAHTOA — missing length
Adjacent = 22cm, angle = 47°. Find opposite
Answer: 23.6cm -
4. Ratio Reverse percentages
A price of £758.67 includes a 21% increase. What was the price before the increase?
Answer: £627.00 -
5. Statistics Mean
The mean of 5 numbers is 35. If 4 of them are 22, 44, 47, 47, what is the missing number?
Answer: 15