Page 21 - Start Up Mathematics_4

Rounding off to the nearest 100

To round off numbers to the nearest 100, look at the digits at the tens place.

• If it is 4 or less, then place zeros at the tens and ones place. The digit at the hundreds
place remains the same.
• If it is 5 or more, then place zeros at the tens and ones place. Add 1 to the digit at the
hundreds place.

Example 7: Round off (a) 826, (b) 4,768 and (c) 2,80,934 to the nearest 100.

Solution: (a) 826 is rounded off to 800 since the digit at the tens place is 2.
(b) 4,768 is rounded off to 4,800 since the digit at the tens place is 6.
(c) 2,80,934 is rounded off to 2,80,900 since the digit at the tens place is 3.

Rounding off to the nearest 1,000

To round off numbers to the nearest 1,000, look at the digits at the hundreds, tens and ones place.
• If it is 4 or less, then place zeros at the hundreds, tens and ones place. Keep the digit
at the thousands place as it is.

• If it is 5 or more, then place zeros at the hundreds, tens and ones place. Also, add 1 to
the digit at the thousands place.
Example 8: Round off (a) 6,578 and (b) 24,352 to the nearest 1,000.

Solution: (a) 6,578 is rounded off to 7,000 since the digit at the hundreds place is 5.

(b) 24,352 is rounded off to 24,000 since the digit at the hundreds place is 3.

EXERCISE 1.3

1. Write the smallest and the greatest 5-digit numbers formed using the given digits.
(a) 7, 4, 3, 1, 8 (b) 5, 0, 2, 8, 3

(c) 9, 1, 6, 2, 0 (d) 8, 0, 7, 0, 4
2. Write the smallest and the greatest 6-digit numbers formed using the given digits.

(a) 2, 3, 7, 8, 5, 1 (b) 6, 0, 9, 3, 0, 4
(c) 8, 2, 1, 3, 2, 5 (d) 9, 4, 6, 5, 0, 9

3. Round off the given numbers to the nearest 10.
(a) 547 (b) 6,912 (c) 43,785 (d) 1,90,273

4. Round off the given numbers to the nearest 100.
(a) 496 (b) 7,319 (c) 75,849 (d) 4,46,755

5. Round off the given numbers to the nearest 1,000.
(a) 7,435 (b) 12,752 (c) 4,75,926 (d) 8,99,128

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