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.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
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.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
4.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
5.Estimate the value of √45, giving your answer to the nearest whole number.
(a)2,025
(b)7
(c)6
(d)22.5
6.Work out an estimate for 588 ÷ 31, by rounding each number to 1 significant figure.
(a)20
(b)19
(c)17
(d)200
7.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
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.Work out an estimate for 397 ÷ 21, by rounding each number to 1 significant figure.
(a)20
(b)200
(c)19
(d)2
10.Tickets to a theme park cost £38.50 for an adult and £19.75 for a child. A family estimates the total cost for 4 adults and 3 children, by rounding each ticket price to the nearest £5. Work out their estimate for the total cost.
(a)£160
(b)£220
(c)£213.25
(d)£200
11.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
12.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
13.Work out an estimate for 312 × 19, by rounding each number to 1 significant figure.
(a)6200
(b)5928
(c)6000
(d)600
14.Amelia has 49 boxes of apples with 21 apples in each box. Work out an estimate for the total number of apples, by rounding each number to 1 significant figure.
(a)1,029
(b)1,500
(c)800
(d)1,000
15.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

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