8/8/2019 Rules in Rounding Off Numbers

1/7

If the number following the digits to be kept for

the answer is less than 5, the digits kept are not

altered.

Examples

4.073 Round off to three digits 4.07

54.37 Round off to two digits 54

10578 Round off to oneSignificant digit 10000

8/8/2019 Rules in Rounding Off Numbers

2/7

If the number following the digits to be kept for

the answer is 5 or greater, add 1 to the digitkept.

Examples

4.073 Round off to two digits 4.1

54.57 Round off to two digits 55

10578Round off to three

Significant digit 10600

8/8/2019 Rules in Rounding Off Numbers

3/7

8/8/2019 Rules in Rounding Off Numbers

4/7

In multiplying or dividing significant figures, the

answer should not have more significant figures

than the measurement having the fewest

significant figures.

1009.79 km 53.44 L

Examples

6 SF 4 SF

18.89577 km/L

18.90 km/L

8/8/2019 Rules in Rounding Off Numbers

5/7

76.02 cm x 4.45 cm x 0.190cm

4 SF 3 SF

62.83053 cm

3

62.8 cm33 SF

1) 20.60 m x 3.71m

2) 43 g 454 L

3) 2.1 m (25.3 m/4 m)

1) 20.60 m x 3.71m 76.426 m2 76.4 m2

2) 43 g 454 L 0.0947137g/L

0.095 g/L

3) 2.1 m (25.3 m/4 m) 13.2825 m 10 m

8/8/2019 Rules in Rounding Off Numbers

6/7

In adding or subtracting significant figures, the

answer should not have more decimal places

than the least accurate.

Examples

13.6 g

+ 4.082 g17.682 g

1 decimal place

3 decimal places

17.7 g

8/8/2019 Rules in Rounding Off Numbers

7/7

64.41 g

- 52.8 g

12.61 g

2 decimal places

1 decimal place

12.6 g

1)1.78m + 40.1m

2)6.211m + 165.0 m + 3.4 m

3) 10.55 cm + 231 cm

4) 365.54

6km 1.8953

6km

41.9 m

174.6 m

242 cm

363.651 km