Strand 3 Accuracy Unit 7 Limits of accuracy Band g
Skills practice A
1 Write the number 1030 correct to
a 1 significant figure
c 3 significant figures
e Explain your answers to parts c and d.
b 2 significant figures
d 4 significant figures.
2 How many significant figures might the number 100 have?
3 350 is accurate to 2 significant figures.
a Explain why John rounded 349 to 350 to 2 s.f.
b Write down two other numbers smaller than 349 which will round to 350 to 2 s.f.
4 2.56 is correct to 2 decimal places.
a Explain why Mary wrote 2.563 as 2.56 to 2 decimal places.
b Write down two more numbers bigger than 2.563 that Mary would still round to 2.56 to
2 decimal places.
c Write down two numbers less than 2.56 which will round up to 2.56 to 2 decimal places.
d What are the biggest and the smallest numbers that can round to 2.56 to 2 decimal places?
5 a Write these numbers correct to 2 significant figures.
i 1.24
ii 1.237
iii 1.1652
iv 1.151
v 1.249
vi 1.249 99
b The number 1.2 is given correct to 2 significant figures. Write this as a range of numbers.
6 All of these numbers have been rounded.
Write down lower and upper bounds for each of them.
a 123
b 1.044
d 3.1416
e 0.0589
g 8.005
h 107.05
i 0.004 07
j 4125
c 3.333
f 1.50
7 All of these numbers have been rounded. Write down lower and upper bounds for each of them.
a 510 correct to the nearest 10
b 2600 correct to the nearest 100
c 23.5 correct to 3 significant figures
d 21.15 correct to 2 decimal places
e 440 correct to 2 significant figures
8 Write each of these as an inequality.
a 230 (correct to the nearest 10)
c 200 (correct to 1 s.f.)
e 0.4 (correct to 1 s.f.)
© Hodder & Stoughton Ltd 2014
b 5.62 (correct to 2 decimal places)
d 200 (correct to 2 s.f.)
f 0.40 (correct to 2 s.f.)
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