Keystones — Lintel
Five GCSE retrieval questions · 29 December 2025 · mathsvault.uk/keystones
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1. Number Converting to standard form
0.084
Answer: 8.4 × 10-2 -
2. Algebra Factorising monic quadratics
Factorise: x² - 8x + 16
Answer: (x - 4)(x - 4) -
3. Geometry SOHCAHTOA — missing length
Hypotenuse = 21cm, angle = 58°. Find adjacent side
Answer: 11.cm -
4. Ratio Mixed ratio problems
Express the first part of 4:5 as a fraction in simplest form
Answer: 4⁄9 -
5. Statistics Mean
The mean of 6 numbers is 28. If 5 of them are 23, 18, 43, 40, 30, what is the missing number?
Answer: 14