Keystones — Lintel
Five GCSE retrieval questions · 23 November 2025 · mathsvault.uk/keystones
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1. Number Converting to standard form
0.00043
Answer: 4.3 × 10-4 -
2. Algebra Factorising monic quadratics
Factorise: x² + x - 2
Answer: (x + 2)(x - 1) -
3. Geometry SOHCAHTOA — missing length
Adjacent = 18cm, angle = 42°. Find opposite
Answer: 16.2cm -
4. Ratio Mixed ratio problems
Simplify: 12:8:12
Answer: 3:2:3 -
5. Statistics Mean
The mean of 6 numbers is 39. If 5 of them are 45, 22, 16, 18, 34, what is the missing number?
Answer: 99