Keystones — Lintel
Five GCSE retrieval questions · 11 December 2025 · mathsvault.uk/keystones
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1. Number Converting to standard form
0.00091
Answer: 9.1 × 10-4 -
2. Algebra Factorising monic quadratics
Factorise: x² + 3x - 18
Answer: (x + 6)(x - 3) -
3. Geometry SOHCAHTOA — missing length
Hypotenuse = 32cm, angle = 56°. Find adjacent side
Answer: 17.9cm -
4. Ratio Mixed ratio problems
Divide 160 in the ratio 1:2:1
Answer: 40, 80 and 40 -
5. Statistics Mean
The mean of 5 numbers is 34. If 4 of them are 47, 40, 48, 18, what is the missing number?
Answer: 17