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 · Non-calculator · 15 questions

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1.Work out an estimate for 6.8 × 41, by rounding each number to 1 significant figure.
(a)28
(b)240
(c)280
(d)350
2.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
3.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
4.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
5.Oliver drives 95 km at an average speed of 50 km/h. Work out an estimate for the time the journey takes, by rounding the distance to the nearest 100 km.
(a)1 hour 54 minutes
(b)30 minutes
(c)1 hour
(d)2 hours
6.Estimate the value of √45, giving your answer to the nearest whole number.
(a)2,025
(b)7
(c)6
(d)22.5
7.A minibus can carry 16 passengers. A school is taking 179 pupils on a trip. By rounding 179 to the nearest 10, work out an estimate for the number of minibuses needed, given that the school cannot hire part of a minibus.
(a)180
(b)12
(c)10
(d)11
8.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
9.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
10.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
11.Grace buys three items costing £9.95, £19.90 and £4.99. Work out an estimate for the total cost, by rounding each price to the nearest pound.
(a)£34.84
(b)£35
(c)£32
(d)£40
12.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
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.Hannah works out 3.1 × 19.6 on her calculator and writes down 6.076. Work out an estimate for 3.1 × 19.6, by rounding each number to 1 significant figure.
(a)6
(b)62
(c)600
(d)60
15.Work out an estimate for 312 × 19, by rounding each number to 1 significant figure.
(a)6200
(b)5928
(c)6000
(d)600

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