Worksheets · Foundation and Higher

Rounding, significant figures and error intervals

3 exam-style questions. Answers and the mark for each step are on the last page.

Question 1Non-calculator · 3 marks
Round each number as instructed.
(a) Round $3.4762$ to 2 decimal places. (1)
(b) Round $48\,350$ to 2 significant figures. (1)
(c) Round $0.006072$ to 1 significant figure. (1)
Question 2Non-calculator · 1 mark
(a) A positive number x is truncated to one decimal place. The result is 5.8. Which interval describes x? (1)
1. 5.75 $\le$ x < 5.85
2. 5.8 < x $\le$ 5.9
3. 5.7 $\le$ x < 5.9
4. 5.8 $\le$ x < 5.9
Question 3Calculator · 5 marks
A newspaper reports that $12\,000$ people went to a concert, correct to 2 significant figures. Every ticket cost exactly £35.
(a) Work out the least possible total amount paid for the tickets. (3)
(b) Tom says, "The greatest possible number of people is $12\,500$ ." Explain why Tom is wrong. (2)

Answers and marks

(a) $3.48$

(b) $48\,000$

(c) $0.006$

(a) 5.8 $\le$ x < 5.9

(a) £402\,500

(b) $12\,500$ rounds to $13\,000$ to 2 significant figures, so the greatest whole number is $12\,499$ .

C1 Saying that $12\,500$ would round to $13\,000$ .
C1 Giving $12\,499$ as the greatest possible number, because people are counted in whole numbers.

Rounding, significant figures and error intervals

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