Keystones — Capstone
Five GCSE retrieval questions · 20 September 2026 · mathsvault.uk/keystones
-
1. Number Rationalising the denominator
Rationalise the denominator: 6/√12
Answer: √3 (or 3√3⁄3) -
2. Algebra Factorising non-monic quadratics
Factorise: 12x² -4x - 8
Answer: (4x - 4)(3x + 2) -
3. Geometry SOHCAHTOA — missing length
Adjacent = 10cm, angle = 33°. Find opposite
Answer: 6.5cm -
4. Ratio Reverse percentages
A price of £777.20 includes a 34% increase. What was the price before the increase?
Answer: £580.00 -
5. Statistics Mean
The mean of 4 numbers is 28. If 3 of them are 22, 23, 36, what is the missing number?
Answer: 31