Keystones — Lintel
Five GCSE retrieval questions · 10 September 2025 · mathsvault.uk/keystones
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1. Number Converting to standard form
0.00011
Answer: 1.1 × 10-4 -
2. Algebra Factorising monic quadratics
Factorise: x² + 2x - 24
Answer: (x + 6)(x - 4) -
3. Geometry SOHCAHTOA — missing length
Adjacent = 22cm, angle = 39°. Find opposite
Answer: 17.8cm -
4. Ratio Mixed ratio problems
In ratio 3:3:2, what fraction is the second part?
Answer: 3⁄8 -
5. Statistics Mean
The mean of 6 numbers is 35. If 5 of them are 15, 43, 40, 31, 30, what is the missing number?
Answer: 51