Printable · GCSE Foundation · ages 14-16

Estimation and checking worksheet — GCSE Foundation

Fifteen questions on "estimation and checking" — DfE statement N14. Print it, or print three versions so neighbours cannot copy by letter; the key gives the letter for each version.

Non-calculator

VersionsA only A + B A + B + Csame questions, different order

AnswersQuestions only With answer key Key only

CalculatorMixed Non-calculator (Paper 1)Calculator (Papers 2 and 3)

New sheet

Estimation and checking worksheet — GCSE Foundation

Maths · GCSE Foundation · N14 · Estimation and checking · Non-calculator · 15 questions

MathsUKwww.geekhero.co.uk

1.Work out an estimate for 397 ÷ 21, by rounding each number to 1 significant figure.
(a)20
(b)200
(c)19
(d)2
2.Amelia estimates 48 × 21 by working out 50 × 20 = 1,000. Work out whether her estimate is an under-estimate or an over-estimate, and by how much.
(a)An over-estimate, by 19
(b)Neither — the estimate is exactly right
(c)An under-estimate, by 8
(d)An over-estimate, by 8
3.Work out an estimate for 6.8 × 41, by rounding each number to 1 significant figure.
(a)28
(b)240
(c)280
(d)350
4.Work out an estimate for 79.3 − 24.6, by rounding each number to the nearest whole number.
(a)55
(b)54
(c)59
(d)54.7
5.A charity bake sale sells 187 cakes at £2.95 each. By rounding each number to 1 significant figure, work out an estimate for the total amount raised.
(a)£600
(b)£400
(c)£561
(d)£570
6.Work out an estimate for 2.9² + 3.1², by rounding each number to the nearest whole number.
(a)18
(b)36
(c)6
(d)12
7.Oliver uses his calculator to work out 25% of 80 and writes down 320. Without using a calculator, work out the correct value of 25% of 80.
(a)16
(b)20
(c)3.2
(d)25
8.Freya types 4² + 3² into her calculator and writes down 49. Work out the correct value of 4² + 3².
(a)14
(b)25
(c)49
(d)12
9.Work out an estimate for 588 ÷ 31, by rounding each number to 1 significant figure.
(a)20
(b)19
(c)17
(d)200
10.A spreadsheet shows that 812 − 397 = 315. Work out an estimate for 812 − 397, by rounding each number to the nearest 100, to check whether the spreadsheet's answer is reasonable.
(a)415
(b)400
(c)300
(d)500
11.Estimate the value of √45, giving your answer to the nearest whole number.
(a)2,025
(b)7
(c)6
(d)22.5
12.Work out an estimate for 312 × 19, by rounding each number to 1 significant figure.
(a)6200
(b)5928
(c)6000
(d)600
13.Work out an estimate for 8,900 ÷ 29, by rounding each number to 1 significant figure.
(a)300
(b)307
(c)450
(d)3,000
14.A school orders 187 packed lunches for a trip. Each packed lunch costs £4.85. The school has £900 to spend. By rounding each number to 1 significant figure, work out an estimate for the total cost and decide whether £900 is enough.
(a)£935, so £900 is not enough
(b)£1,000, so £900 is not enough
(c)£800, so £900 is enough
(d)£950, so £900 is not enough
15.Freya uses her calculator to work out 7² and writes down 14. Work out the correct value of 7².
(a)49
(b)14
(c)9
(d)77

Build your own mix at the worksheet builder.