Page 20 - Viva

Rounding Off Numbers There are about 20
When we are not sure of the exact number, we use the birds on this tree.
word about before it. This gives a rough estimation

of the number. We can also say that the number has
been rounded off. In this class, we will learn how to
round off a number to the nearest 10, 100 or 1000.

Rounding Off to the Nearest 10
To round off a number to the nearest ten, look at the

digit at the ones place.
• If the digit at the ones place is less than 5, then write zero at the ones place and let

the digit at the tens place remain as it is.
• If the digit at the ones place is 5 or more, then write zero at the ones place. Also, add
1 to the digit at the tens place.

Example 11: Round off (a) 43 and (b) 87 to the nearest 10.

Solution: (a) 43 is rounded off to 40 since the digit at the ones place is 3 which is less
than 5.

(b) 87 is rounded off to 90 since the digit at the ones place is 7 which is more
than 5.

Rounding Off to the Nearest 100

To round off a number to the nearest hundred, look at the digit at the tens place.
• If the digit at the tens place is less than 5, then write zeros at the tens and ones
places. The digit at the hundreds place remains the same.

• If the digit at the tens place is 5 or more, then write zeros at the tens and ones
places. Also, add 1 to the digit at the hundreds place.

Example 12: Round off (a) 243 and (b) 1887 to the nearest 100.

Solution: (a) 243 is rounded off to 200 because the digit at the tens place is 4.

(b) 1887 is rounded off to 1900 because the digit at the tens place is 8.

Rounding Off to the Nearest 1000
To round off a number to the nearest thousand, look at the digit at the hundreds place.

• If the digit at the hundreds place is less than 5, then write zeros at the hundreds, tens
and ones places. Keep the digit at the thousands place as it is.

• If the digit at the hundreds place is 5 or more, then write zeros at the hundreds, tens
and ones places. Also, add 1 to the digit at the thousands place.

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