Page 18 - Math Skill - 4

16 Maths

Let’s Attempt

Example: Round off each of the following numbers to the nearest ten.
(a) 47 (b) 924
Solution: (a) The given number is 47. (b) The given number is 924.
Its ones digit is 7 and 7 > 5. Its ones digit is 4 and 4 < 5.
Thus, 47 is rounded off to 50. Thus, 924 is rounded off to 920.

Rounding off Numbers to the Nearest Hundred

To round off a given number to the nearest hundred, we find out the multiple of 100 which is
nearest to the given number.

For example, consider the numbers 723 and 779. Both the numbers lie between 700 and 800. Let
us draw a number line to locate these numbers.
Middle most number
723 779

700 710 720 730 740 750 760 770 780 790 800

On the number line, 723 is nearer to 700, so we round off 723 to 700.

On the number line, 779 is nearer to 800, so we round off 779 to 800.
Thus, the rules for rounding off a number to the nearest hundred are as follows:

™ If the digit at tens place is less than 5, replace ones and tens digit by 0 and keep the other
digits as they are.

™ If the digit at tens place is 5 or greater than 5, increase the hundreds digits by 1 and
replace the tens and ones digits by 0.

Let’s Attempt

Example: Round off each of the following numbers to the nearest hundred.
(a) 1923 (b) 16465
Solution: (a) The given number is 1923. (b) The given number is 16465.

Its tens digit is 2 and 2 < 5. Its tens digit is 6 and 6 > 5.
Thus, 1923 is rounded off to 1900. Thus, 16465 is rounded off to 16500.

Rounding off Numbers to the Nearest Thousand

To round off a given number to the nearest thousand, we find out the multiple of 1000 which is
nearest to the given number.
For example, consider the numbers 8250 and 8750. Both the numbers lie between 8000 and
9000. Let us draw a number line and locate these numbers.

Middle most number

8000 8250 8500 8750 9000