Page 104 - Math Skill - 5

102 Maths

Rounding off Decimals
Like numbers, we may round off decimals to the nearest tenths, hundredths, thousandths and
so on. To round off decimals, we follow these steps:

Step 1: If the digit to the right of the rounding place is greater than or equal to 5, add 1 to the
digit at the rounding place otherwise do not change the digit at the rounding place.

Step 2: Replace all digits to the right of the rounding place by 0 or simply drop all digits.

Let’s learn through examples.

Let’s Attempt

Example 1: Round off the following decimals to the nearest ones.

(a) 6.7 (b) 7.29

Solution: (a) In 6.7, the digit to the right (b) In 7.29, the digit to the right
of the ones place is 7. of the ones place is 2.

Since, 7 > 5 Since, 2 < 5

Thus, 6.7 is rounded off to Thus, 7.29 is rounded off to
the nearest ones as 7. the nearest ones as 7.

Example 2: Round off the following to the nearest tenths.
(a) 5.23 (b) 8.05 (c) 4.98

Solution: (a) In 5.23, the digit to the right (b) In 8.05, the digit to the right
of the tenths place is 3. of the tenths place is 5.

Since, 3 < 5 Thus, 8.05 is rounded off to 8.1.
Thus, 5.23 is rounded off to 5.2.

(c) In 4.98, the digit to the right of the tenths place is 8.
Since, 8 > 5

Thus, 4.98 is rounded off to 5.0 or 5.
Example 3: Round off the following to the nearest hundredths.

(a) 1.347 (b) 397.506 (c) 32.871

Solution: (a) 1.347 rounded off to the nearest hundredths is 1.35. (Since, 7 > 5)
(b) 397.506 is rounded off to 397.51. (Since, 6 > 5)
(c) 32.871 is rounded off to 32.87. (Since, 1 < 5)

Example 4: Round off the following to the nearest thousandths.
(a) 1.4336 (b) 631.0582

Solution: (a) In 1.4336, 6 > 5 (b) In 631.0582, 2 < 5
Thus, 1.4336 is rounded Thus, 631.0582 is rounded off to 631.058.

off to 1.434.