Page 19 - ICSE Math 4

2. Write the smallest and the largest 6-digit numbers that can be 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. Write the smallest and the largest 6-digit numbers that can be formed using the
digits 2, 7, 0, 5 and 3 by repea ng 0 two mes.

4. Form any 6 possible 6-digit even numbers using the digits 3, 5, 6, 4, 0 and 9 without
repea ng the digits.

5. Form any 6 possible 5-digit odd numbers using the digits 9, 4, 2 and 3 by repea ng
the digit 2 twice.

Rounding Off Numbers

We round off a number to get its approximate es ma on. We already know how to
round off a number to the nearest 10; 100 or 1,000. Let’s quickly revise them with larger
numbers.

Rounding Off to the Nearest 10

To round off a number to the nearest 10, look at the digit at the ones place.

• If it is 4 or less, then write 0 at the ones place without changing the remaining
digits.

• If it is 5 or more, then write 0 at the ones place and add 1 to the digit at the tens
place.

Example 13: Round off (a) 2,354 and (b) 30,795 to the nearest 10.
Solu on: (a) 2,354 is rounded off to 2,350 since the digit at the ones place is 4.

(b) 30,795 is rounded off to 30,800 since the digit at the ones place is 5.

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 write zeros at the tens and ones places. The digits at other
places remain the same.
• If it is 5 or more, then write zeros at the tens and ones places. Add 1 to the digit at

the hundreds place.

Example 14: Round off (a) 4,768 and (b) 2,80,934 to the nearest 100.

Solu on: (a) 4,768 is rounded off to 4,800 since the digit at the tens place is 6.

(b) 2,80,934 is rounded off to 2,80,900 since the digit at the tens place is 3.

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