Keystones — Capstone
Five GCSE retrieval questions · 7 March 2026 · mathsvault.uk/keystones
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1. Number Rationalising the denominator
Rationalise the denominator: 1/√2
Answer: √2⁄2 -
2. Algebra Factorising non-monic quadratics
Factorise: 16x² + 4x - 20
Answer: (4x - 4)(4x + 5) -
3. Geometry SOHCAHTOA — missing length
Adjacent = 19cm, angle = 53°. Find opposite
Answer: 25.2cm -
4. Ratio Reverse percentages
A price of £798.00 includes a 20% increase. What was the price before the increase?
Answer: £665.00 -
5. Statistics Mean
The mean of 4 numbers is 36. If 3 of them are 34, 42, 38, what is the missing number?
Answer: 30