Keystones — Lintel
Five GCSE retrieval questions · 25 February 2025 · mathsvault.uk/keystones
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1. Number Converting to standard form
0.0048
Answer: 4.8 × 10-3 -
2. Algebra Factorising monic quadratics
Factorise: x² - 13x + 42
Answer: (x - 6)(x - 7) -
3. Geometry SOHCAHTOA — missing length
Hypotenuse = 30cm, angle = 60°. Find adjacent side
Answer: 15cm -
4. Ratio Mixed ratio problems
Express the first part of 5:3 as a fraction in simplest form
Answer: 5⁄8 -
5. Statistics Mean
The mean of 5 numbers is 20. If 4 of them are 24, 30, 41, 21, what is the missing number?
Answer: -16