Keystones — Lintel
Five GCSE retrieval questions · 3 May 2025 · mathsvault.uk/keystones
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1. Number Converting to standard form
36000000
Answer: 3.6 × 107 -
2. Algebra Factorising monic quadratics
Factorise: x² + 4x - 21
Answer: (x + 7)(x - 3) -
3. Geometry SOHCAHTOA — missing length
Adjacent = 25cm, angle = 48°. Find opposite
Answer: 27.8cm -
4. Ratio Mixed ratio problems
In ratio 3:4:3, what fraction is the second part?
Answer: 4⁄10 -
5. Statistics Mean
The mean of 5 numbers is 28. If 4 of them are 21, 26, 21, 46, what is the missing number?
Answer: 26