Rounding Decimals to the Nearest Whole Number

Rules for rounding decimals to the nearest whole number:

● To round a decimal to the nearest whole number analyse the digit at the first decimal place i.e., tenths place.

● If the tenths place value is 5 or greater than 5, then the digit at the ones place increases by 1 and the digits at the tenths place and thereafter becomes 0.

For example;

(i) 9.63 →

In 9.63 analyse the digit at the tenths place. Here 6 is more than 5. Therefore we have to round the number up to the nearest whole number 10.

(ii) 78.537 →

In 78.537 analyse the digit at the tenths place. Here 5 is equal to 5. Therefore we have to round the number up to the nearest whole number 79.

● If the tenths place value is less than 5, then the digit at the ones place remains the same but the digits at the tenths place and thereafter becomes 0.

For example;

(i) 7.21 →

In 7.21 analyse the digit at the tenths place. Here 2 is less than 5. Therefore we have to round the number down to the nearest whole number 7.

(ii) 13.48 →

In 13.48 analyse the digit at the tenths place. Here 4 is less than 5. Therefore we have to round the number down to the nearest whole number 13.

Worked-out examples on rounding decimals to the nearest whole number:

To round a decimal to the nearest whole number follow the explanation step-by-step how to round up or round down the decimal to the nearest whole number.

Round off the following to the nearest whole number.

(a) 51.7

Solution:

51.7

The digit at the tenths place is 7 and 7 > 5.

The whole number part of 51.7 increases by 1 and the digit to the right of decimal point means the tenths place becomes zero (rounded up).

Therefore, 51.7 rounded off to the nearest whole number as 52.

(b) 147.28

Solution:

147.28

The digit at the tenths place is 2 and 2 < 5.

The digit at the ones place remains unchanged and the digits to the right of the decimal point means the tenths place and hundredths place becomes 0 (rounded down).

Therefore, 147.28 rounded off to the nearest whole number 147.

● Related Concept

● Decimals

● Decimal Numbers

● Decimal Fractions

● Like and Unlike Decimals

● Comparing Decimals

● Decimal Places

● Conversion of Unlike Decimals to Like Decimals

● Decimal and Fractional Expansion

● Terminating Decimal

● Non-Terminating Decimal