Divisibility criteria of 3:

A number is divisible by 3 if the sum of the digits of the number is divisible by three.

The rule of divisibility of the number 3 is simple.

Example 1.

Is 18 divisible by 3?

The sum of the digits of the number 18

1 + 8 = 9

The number 9 is divisible by 3

9 ÷ 3 = 3

18 is divisible by 3 since the sum of the digits of the number is divisible by three.

Example 2.

Is 183 divisible by 3?

The sum of the digits of the number 183

1 + 8 + 3 = 12

The number 12 is divisible by 3

12 ÷ 3 = 4

183 is divisible by 3 since the sum of the digits of the number is divisible by three.

Example 3.

Is 184 divisible by 3?

The sum of the digits of the number 184

1 + 8 + 4 = 13

The number 13 is not divisible by 3

13 ÷ 3 = 4 R 1

184 is not divisible by 3 since the sum of the digits of the number is not divisible by three.