Keystones — Lintel
Five GCSE retrieval questions · 30 October 2025 · mathsvault.uk/keystones
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1. Number Converting to standard form
0.00094
Answer: 9.4 × 10-4 -
2. Algebra Factorising monic quadratics
Factorise: x² + 2x - 48
Answer: (x + 8)(x - 6) -
3. Geometry SOHCAHTOA — missing length
Hypotenuse = 19cm, angle = 36°. Find adjacent side
Answer: 15.4cm -
4. Ratio Mixed ratio problems
Express the first part of 2:3 as a fraction in simplest form
Answer: 2⁄5 -
5. Statistics Mean
The mean of 6 numbers is 27. If 5 of them are 17, 38, 21, 25, 38, what is the missing number?
Answer: 23