Keystones — Lintel
Five GCSE retrieval questions · 25 October 2026 · mathsvault.uk/keystones
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1. Number Converting to standard form
0.00038
Answer: 3.8 × 10-4 -
2. Algebra Factorising monic quadratics
Factorise: x² + 4x - 21
Answer: (x + 7)(x - 3) -
3. Geometry SOHCAHTOA — missing length
Adjacent = 21cm, angle = 36°. Find opposite
Answer: 15.3cm -
4. Ratio Mixed ratio problems
In ratio 1:3:4, what fraction is the second part?
Answer: 3⁄8 -
5. Statistics Mean
Calculate the mean of: 31, 36, 19, 11, 5, 25
Answer: 21.2