Keystones — Capstone
Five GCSE retrieval questions · 6 March 2026 · mathsvault.uk/keystones
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1. Number Rationalising the denominator
Rationalise: 6/√5
Answer: 6√5⁄5 -
2. Algebra Factorising non-monic quadratics
Factorise: 8x² -6x - 9
Answer: (2x - 3)(4x + 3) -
3. Geometry SOHCAHTOA — missing length
Adjacent = 18cm, angle = 30°. Find opposite
Answer: 10.4cm -
4. Ratio Reverse percentages
A price of £669.44 includes a 28% increase. What was the price before the increase?
Answer: £523.00 -
5. Statistics Mean
The mean of 6 numbers is 33. If 5 of them are 35, 36, 43, 47, 43, what is the missing number?
Answer: -6