Divisibility Rule of 9: Rule, Examples

Divisibility Rule of 9

A number is divisible by 9 if the sum of its digits is a multiple of 9 (like 9, 18, 27, 36, etc.).

If the sum is divisible by 9, then the whole number is also divisible by 9!

Steps to Check Divisibility by 9

1. Write down the number.

2. Add up all the digits.

3. Check if the sum is a multiple of 9.

4. If yes, the number is divisible by 9.

Examples

Example 1: Is 729 divisible by 9?

1. Number: 729

2. Add the digits: 7 + 2 + 9 = 18

3. 18 is a multiple of 9 (18 ÷ 9 = 2)

729 is divisible by 9.

Example 2: Is 458 divisible by 9?

1. Number: 458

2. Add the digits: 4 + 5 + 8 = 17

3. 17 is not a multiple of 9.

458 is not divisible by 9.

Try It Yourself:

Are they divisible by 9?
1. 981
2. 1215
3. 354