Keystones — Lintel
Five GCSE retrieval questions · 22 October 2026 · mathsvault.uk/keystones
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1. Number Converting to standard form
0.0046
Answer: 4.6 × 10-3 -
2. Algebra Factorising monic quadratics
Factorise: x² + x - 20
Answer: (x + 5)(x - 4) -
3. Geometry SOHCAHTOA — missing length
Adjacent = 13cm, angle = 31°. Find opposite
Answer: 7.8cm -
4. Ratio Mixed ratio problems
Express the first part of 6:3 as a fraction in simplest form
Answer: 2⁄3 -
5. Statistics Mean
The mean of 6 numbers is 30. If 5 of them are 21, 32, 41, 38, 47, what is the missing number?
Answer: 1