Keystones — Lintel
Five GCSE retrieval questions · 4 October 2025 · mathsvault.uk/keystones
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1. Number Converting to standard form
17000000
Answer: 1.7 × 107 -
2. Algebra Factorising monic quadratics
Factorise: x² - 13x + 42
Answer: (x - 7)(x - 6) -
3. Geometry SOHCAHTOA — missing length
Adjacent = 26cm, angle = 45°. Find opposite
Answer: 26cm -
4. Ratio Mixed ratio problems
Express the first part of 3:4 as a fraction in simplest form
Answer: 3⁄7 -
5. Statistics Mean
The mean of 5 numbers is 35. If 4 of them are 24, 50, 48, 40, what is the missing number?
Answer: 13