Page 38 - Maths Skills - 7

36 Maths

● If the tenths digit is equal to or greater than 5, increase the ones digit by 1 and replace all digits in the
decimal parts with 0s.

ROUNDING OFF DECIMALS CORRECT TO ONE DECIMAL PLACE
● When the digits in the hundredths place is less than 5, the digits at the hundredths and following places are
replaced by zeros.

16.5 2 6 → 16.500
At hundredths place 2 < 5, therefore 16.526 is rounded off as 16.500 = 16.5 correct up to one decimal place.
● When the digits in the hundredth place is 5 or more, the digit at the tenths place is increased by 1 and the
following digits become 0.

35.6 7 2 → 35.700
At hundredths place 7 > 5, therefore 35.672 is rounded off as 35.700 = 35.7 correct up to one decimal place.

ROUNDING OFF DECIMALS CORRECT TO TWO DECIMAL PLACES
● When the digit in the thousandths place is less than 5, the digits at the thousandths and the following places
are replaced by 0.

58. 61 2 → 58.610
At thousandths place 2 < 5, therefore 58.612 is rounded off as 58.610 = 58.61 (correct up to 2 decimal
places).
● When the digit in thousandths place is 5 or more, then the digit in the hundredths place is increased by
1 and the following digits become 0.

175. 76 9 → 175.770

At thousandths place 9 > 5, therefore 175.769 is rounded off as 175.770 = 175.77 (correct up to 2 decimal
places).

Let’s Attempt

Example: Round off the following numbers to the nearest ones.

(i) 17.35 (ii) 3.056 (iii) 181.795 (iv) 6.530

Solution: (i) 3 is at tenths place which is less than 5. Therefore to round off the decimal to the nearest ones
replace both 3 and 5 by 0s.

17.35 → 17.00 = 17

(ii) In 3.056, at tenths place 0 < 5 therefore, 3.056 can be rounded off as 3.000.

3.056 → 3.000 = 3

(iii) In 181.795, at tenths place 7 > 5 therefore, 181.795 can be rounded off by increasing ones digit
by 1 and replacing all digits of the decimal part by 0s.

181.795 → 182.000 = 182

(iv) In 6.530, at tenths place 5 = 5, therefore, 6.530 can be rounded off as 7.000.

6.530 → 7.000 = 7