Keystones — Capstone
Five GCSE retrieval questions · 20 April 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: 16x² -4x - 12
Answer: (4x - 4)(4x + 3) -
3. Geometry SOHCAHTOA — missing length
Adjacent = 24cm, angle = 51°. Find opposite
Answer: 29.6cm -
4. Ratio Reverse percentages
A price of £563.86 includes a 21% increase. What was the price before the increase?
Answer: £466.00 -
5. Statistics Mean
The mean of 6 numbers is 20. If 5 of them are 16, 15, 28, 21, 50, what is the missing number?
Answer: -10