Keystones — Lintel
Five GCSE retrieval questions · 21 February 2026 · mathsvault.uk/keystones
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1. Number Converting to standard form
0.00011
Answer: 1.1 × 10-4 -
2. Algebra Factorising monic quadratics
Factorise: x² - 13x + 42
Answer: (x - 7)(x - 6) -
3. Geometry SOHCAHTOA — missing length
Hypotenuse = 25cm, angle = 46°. Find adjacent side
Answer: 17.4cm -
4. Ratio Mixed ratio problems
Divide 60 in the ratio 1:1:3
Answer: 12, 12 and 36 -
5. Statistics Mean
The mean of 6 numbers is 23. If 5 of them are 26, 22, 23, 48, 17, what is the missing number?
Answer: 2