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

MathsUKwww.geekhero.co.uk

1.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
2.Work out an estimate for 113 + 491, by rounding each number to the nearest 100.
(a)700
(b)500
(c)600
(d)604
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.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
5.Work out an estimate for 397 ÷ 21, by rounding each number to 1 significant figure.
(a)20
(b)200
(c)19
(d)2
6.Work out an estimate for 37 × 84, by rounding each number to 1 significant figure.
(a)3200
(b)2400
(c)120
(d)3108
7.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
8.Work out an estimate for 588 ÷ 31, by rounding each number to 1 significant figure.
(a)20
(b)19
(c)17
(d)200
9.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
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.Light travels at 2.998 × 10⁸ metres per second. A distant object in space is 3.1 × 10¹⁵ metres from Earth. Work out an estimate for the number of seconds light takes to travel from the object to Earth, by rounding each number to 1 significant figure.
(a)9 × 10²³ seconds
(b)3 × 10⁷ seconds
(c)1 × 10⁻⁷ seconds
(d)1 × 10⁷ seconds
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.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
15.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

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