Keystones — Lintel
Five GCSE retrieval questions · 18 March 2025 · mathsvault.uk/keystones
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1. Number Converting to standard form
0.00028
Answer: 2.8 × 10-4 -
2. Algebra Factorising monic quadratics
Factorise: x² + 3x - 40
Answer: (x + 8)(x - 5) -
3. Geometry SOHCAHTOA — missing length
Hypotenuse = 31cm, angle = 31°. Find adjacent side
Answer: 26.6cm -
4. Ratio Mixed ratio problems
Divide 65 in the ratio 2:1:2
Answer: 26, 13 and 26 -
5. Statistics Mean
The mean of 5 numbers is 38. If 4 of them are 16, 25, 33, 16, what is the missing number?
Answer: 100