1. Round off the following numbers to the number of significant figures shown in brackets:
(a) 4.472 (to 3 sig. fig.) | (b) 4.49 (to 2 sig. fig.) |
(c) 0.0147 (to 2 sig. fig.) | (d) 924.4 (to 2 sig. fig.) |
(e) 4.794 (to 1 sig. fig.) | (f) 0.729 (to 2 sig. fig.) |
(g) 4.2447 (to 4 sig. fig.) | (h) 92444 (to 1 sig. fig.) |
(i) 2.79 × 20.2 (to 2 sig. fig.) | (j) 9.42 × 20 (to 2 sig. fig.) |
2. Round the following to the degree of accuracy stated: | ||
(a) 47 744 people at a football match (to the nearest thousand people) | ||
(b) A mass of 12.49 kg (to the nearest kg) | ||
(c) A salary of $32,449 (to the nearest hundred dollars) | ||
(d) A cricketer's score of 99 (to the nearest ten runs) |
3. (a) In the table below, round each number to 1 significant figure and calculate.
(b) Calculate the answer accurately and round it to 4 significant figures.
Calculation |
(a) Estimate |
(b) Accurate answer (rounded to 4 sig. fig.) |
9.47 + 4.7 |
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34.5 × 2.9 |
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(9.42)^{ 2} |
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^{8.36}⁄_{4.21} |
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4.99 − (5.74 + 3.2) |
4.Round off the following numbers to the number of decimal places (d.p.) shown:
(a) 4.79 (to 1 d.p.)
(b) 4.497 (to 2 d.p.)
(c) 0.097 (to 2 d.p.)
(d) 7.2944 (to 3 d.p.)
(e) 427.2994 (to 1 d.p.)
(f) 49.94 (to 0 d.p.)
5. Complete the table, by estimating the cost of each item to 1 significant figure:
Purchase |
Estimated cost |
Accurate cost |
4 cakes at $4.99 each |
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2 buns at 99c each |
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7 biscuits at 22 cents each |
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2 cans of drink at $1.84 each |
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4 loaves at $2.24 each |
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Totals |