Page 19 - Math Skill - 5

Large Numbers 17

Finding the Total Number Exist in 1, 2, 3, 4 Digit Numbers

1-Digit Numbers

1 is the smallest 1-digit number and 9 is the greatest 1-digit number.
Difference = 9 – 1 = 8 Total numbers of 1 digit number = 8 + 1 (including 1) = 9

2-Digit Numbers

10 is the smallest 2-digit number and 99 is the greatest 2-digit number.

Difference = 99 – 10 = 89 Total numbers of 2-digit number = 89 +1 (including 10) = 90
3-Digit Numbers

100 is the smallest 3-digit number and 999 is the greatest 3-digit number.

Difference = 999 – 100 = 899 Total numbers of 4-digit number = 8999 +1 (including 1000) = 9000

4-Digit Numbers
1000 is the smallest 4-digit number and 9999 is the greatest 4-digit number.

Difference = 9999 – 1000 = 8999 Total numbers of 4-digit number = 8999 +1 (including 1000) = 9000

Similarly, you can find the total numbers of any digit number.

Forming Numbers Using Given Digits

We have already learnt to form 5 or 6-digit numbers with the given digits. Let’s now extend the
same for 7-digit numbers and beyond through the following examples.

Let’s Attempt

Example 1: Write the greatest and the smallest 7-digit numbers by using the digits 1, 2, 3, 4, 5,
6 and 7 only once.

Solution: Greatest number: To form the greatest 7-digit number from the given digits,
arrange the digits in descending order.

7 > 6 > 5 > 4 > 3 > 2 > 1 Descending order
Thus, the required greatest number is 76,54,321.

Smallest number: Similarly, to form the smallest 7-digit number from the given
digits, arrange the digits in an ascending order.

1 < 2 < 3 < 4 < 5 < 6 < 7 Ascending order
Thus, the required smallest number is 12,34,567.

Example 2: Write the smallest 6-digit number using the digits 0, 2, 3, 4, 5, 1 without repeating
the digits.
Solution: Write the smallest digit on the extreme left.

Write the next smallest digit on its right and so on.
The smallest number is 1,02,345