Keystones — Lintel
Five GCSE retrieval questions · 11 October 2025 · mathsvault.uk/keystones
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1. Number Converting to standard form
0.0026
Answer: 2.6 × 10-3 -
2. Algebra Factorising monic quadratics
Factorise: x² - 9x + 18
Answer: (x - 6)(x - 3) -
3. Geometry SOHCAHTOA — missing length
Adjacent = 25cm, angle = 30°. Find opposite
Answer: 14.4cm -
4. Ratio Mixed ratio problems
Express the first part of 5:3 as a fraction in simplest form
Answer: 5⁄8 -
5. Statistics Mean
The mean of 5 numbers is 28. If 4 of them are 46, 41, 22, 20, what is the missing number?
Answer: 11