Keystones — Lintel
Five GCSE retrieval questions · 28 November 2010 · mathsvault.uk/keystones
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1. Number Converting to standard form
Write 970,000,000 in standard form
Answer: 9.7 × 108 -
2. Algebra Factorising monic quadratics
Factorise: x² - 4x - 21
Answer: (x + 3)(x - 7) -
3. Geometry SOHCAHTOA — missing length
Adjacent = 29cm, angle = 51°. Find opposite. Give your answer to 2 decimal places
Answer: 35.81cm -
4. Ratio Mixed ratio problems
Simplify the ratio 3 litres : 400 ml
Answer: 15:2 -
5. Statistics Mean
The mean of 4 numbers is 30. If 3 of them are 17, 31, 31, what is the missing number?
Answer: 41