ABSTRACT
Hence a rounding-off error has occurred.
Problem 3. Without using a calculator, determine an approximate value of:
(a) 11.7 × 19.1 9.3 × 5.7 (b)
2.19 × 203.6 × 17.91 12.1 × 8.76
(a) 11.7 × 19.1 9.3 × 5.7 is approximately equal to
10 × 20 10 × 5
i.e. about 4
(By calculator, 11.7 × 19.1 9.3 × 5.7 = 4.22, correct to 3
significant figures.)
(b) 2.19 × 203.6 × 17.91 12.1 × 8.76 ≈
2 × 20 200 × 202 1 10 × 101
= 2 × 20 × 2 after cancelling,
i.e. 2.19 × 203.6 × 17.91
12.1 × 8.76 ≈ 80
(By calculator, 2.19 × 203.6 × 17.91 12.1 × 8.76 ≈ 75.3,
correct to 3 significant figures.)
Now try the following Practice Exercise
Practice Exercise 16 Errors (Answers on page 658)
In Problems 1 to 5 state which type of error, or errors, have been made: 1. 25 × 0.06 × 1.4 = 0.21 2. 137 × 6.842 = 937.4
3. 24 × 0.008
12.6 = 10.42
4. For = c. When = 03 Pa and V = 0.54 m3 then c = 55836Pa m3.
