Printable · GCSE Foundation · ages 14-16

Rounding, significant figures and error intervals worksheet — GCSE Foundation

Fifteen questions on "rounding, significant figures and error intervals" — DfE statement N15. Print it, or print three versions so neighbours cannot copy by letter; the key gives the letter for each version.

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Rounding, significant figures and error intervals worksheet — GCSE Foundation

Maths · GCSE Foundation · N15 · Rounding, significant figures and error intervals · 15 questions

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1.A supermarket sells apples at £1.85 per kg. Anna buys 3.6 kg of apples. Estimate the cost by rounding each number to 1 significant figure before multiplying. Work out Anna's estimate.
(a)£6.66
(b)£8
(c)£7.60
(d)£7.40
2.A digital timer truncates every time to 1 decimal place. It shows a swimmer's time for one length as 12.3 seconds. Using t for the swimmer's actual time in seconds, write down the error interval for t.
(a)12.25 ≤ t < 12.35
(b)12.3 < t ≤ 12.4
(c)12.3 ≤ t < 12.4
(d)12.3 ≤ t ≤ 12.4
3.Round 0.0759 to 2 decimal places.
(a)0.08
(b)0.07
(c)0.076
(d)0.1
4.The length of a nail is 12 cm, correct to the nearest centimetre. Using L for the length of the nail in centimetres, write down the error interval for L.
(a)11.5 ≤ L < 12.5
(b)11.5 < L < 12.5
(c)11 ≤ L < 13
(d)11.5 ≤ L ≤ 12.5
5.A measuring jug shows a volume of 340 ml, correct to the nearest 20 ml. Work out the smallest possible volume in the jug.
(a)330 ml
(b)320 ml
(c)335 ml
(d)350 ml
6.To estimate the cost of buying 38.7 m of rope at £21.40 per metre, both numbers are first rounded to 1 significant figure. Work out the estimate.
(a)£819
(b)£840
(c)£60
(d)£800
7.Round 592.5 to the nearest 10.
(a)600
(b)500
(c)590
(d)595
8.Round 3.947 to 2 decimal places.
(a)4.0
(b)3.94
(c)3.95
(d)3.9
9.A number, y, is equal to 8.2 when rounded to 1 decimal place. Write down the error interval for y.
(a)8.15 ≤ y < 8.25
(b)8.15 < y < 8.25
(c)8.1 ≤ y < 8.2
(d)8.2 ≤ y < 8.3
10.A charity trek covers 830 miles over roughly 19 days. By rounding each number to 1 significant figure, work out an estimate for the number of miles walked per day.
(a)4 miles
(b)830 miles
(c)41.5 miles
(d)40 miles
11.A quantity surveyor calculates a length as 24.6851 m. Round this length to 2 decimal places.
(a)24.7
(b)24.685
(c)24.68
(d)24.69
12.Round 0.006852 to 2 significant figures.
(a)0.0069
(b)0.0068
(c)0.007
(d)0.00685
13.A block of butter has a mass of 250 g, correct to the nearest 10 g. Using m for the mass of the block in grams, write down the error interval for m.
(a)240 ≤ m < 250
(b)245 ≤ m < 255
(c)245 < m ≤ 255
(d)240 ≤ m < 260
14.Four friends share a restaurant bill of £53.90 equally. A calculator gives each share as 13.475. Work out how much each friend should pay.
(a)£13.47
(b)£13.48
(c)£13.50
(d)£13.40
15.A recipe needs 0.485 kg of flour per cake. A bakery estimates its flour order by rounding this amount to 1 significant figure, then multiplying by the 60 cakes it plans to bake. Work out the bakery's estimate for the total flour needed, in kg.
(a)29.4 kg
(b)24 kg
(c)29.1 kg
(d)30 kg

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