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.

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Estimation and checking worksheet — GCSE Foundation

Maths · GCSE Foundation · N14 · Estimation and checking · 15 questions

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1.A country's population is 8,340,000, and it is estimated that 1,950,000 of them live in the capital city. By rounding each number to 1 significant figure, work out an estimate for the number of people who do not live in the capital city.
(a)6,300,000
(b)8,000,000
(c)6,390,000
(d)6,000,000
2.A rectangular field measures 19.6 m by 48.3 m. Work out an estimate for the area of the field, by rounding each length to 1 significant figure.
(a)800 m²
(b)70 m²
(c)1,000 m²
(d)140 m²
3.Work out an estimate for 113 + 491, by rounding each number to the nearest 100.
(a)700
(b)500
(c)600
(d)604
4.Work out an estimate for 588 ÷ 31, by rounding each number to 1 significant figure.
(a)20
(b)19
(c)17
(d)200
5.Work out an estimate for 6.8 × 41, by rounding each number to 1 significant figure.
(a)28
(b)240
(c)280
(d)350
6.Work out an estimate for 397 ÷ 21, by rounding each number to 1 significant figure.
(a)20
(b)200
(c)19
(d)2
7.A cinema has 21 rows of seats with 29 seats in each row. Work out an estimate for the number of people the cinema can hold, by rounding each number to 1 significant figure.
(a)6,000
(b)60
(c)50
(d)600
8.Work out an estimate for 89 + 52, by rounding each number to the nearest 10.
(a)141
(b)130
(c)150
(d)140
9.Estimate the value of √45, giving your answer to the nearest whole number.
(a)2,025
(b)7
(c)6
(d)22.5
10.Work out an estimate for 6.4 × 3.9, by rounding each number to the nearest whole number.
(a)18
(b)25
(c)24
(d)28
11.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
12.Work out an estimate for 37 × 84, by rounding each number to 1 significant figure.
(a)3200
(b)2400
(c)120
(d)3108
13.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
14.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
15.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

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