Keystones — Lintel
Five GCSE retrieval questions · 7 October 2025 · mathsvault.uk/keystones
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1. Number Converting to standard form
0.00027
Answer: 2.7 × 10-4 -
2. Algebra Factorising monic quadratics
Factorise: x² - 7x + 12
Answer: (x - 3)(x - 4) -
3. Geometry SOHCAHTOA — missing length
Hypotenuse = 32cm, angle = 51°. Find adjacent side
Answer: 20.cm -
4. Ratio Mixed ratio problems
Express the first part of 3:5 as a fraction in simplest form
Answer: 3⁄8 -
5. Statistics Mean
The mean of 5 numbers is 25. If 4 of them are 45, 49, 33, 33, what is the missing number?
Answer: -35