Keystones — Capstone
Five GCSE retrieval questions · 13 January 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: 4x² + 0x - 16
Answer: (2x - 4)(2x + 4) -
3. Geometry SOHCAHTOA — missing length
Adjacent = 15cm, angle = 50°. Find opposite
Answer: 17.9cm -
4. Ratio Reverse percentages
A price of £584.96 includes a 28% increase. What was the price before the increase?
Answer: £457.00 -
5. Statistics Mean
The mean of 6 numbers is 33. If 5 of them are 15, 35, 40, 17, 44, what is the missing number?
Answer: 47