Divisibility Rules for 3 and 9

Divisibility Rule for 3

If the sum of the digits of a number is divisible by 3, then the number is divisible by 3.

Some examples of numbers divisible by 3 are as follows.

• The number 85203 is divisible by 3 because the sum of its digits 8+5+2+0+3=18 is divisible by 3.
• The number 79154 is not divisible by 3 because the sum of its digits 7+9+1+5+4=26 is not divisible by 3.

Divisibility Rule for 9

If the sum of the digits of a number is divisible by 9, then the number is divisible by 9.

Some examples of numbers divisible by 9 are as follows.

• The number 51984 is divisible by 9 because the sum of its digits 5+1+9+8+4=27 is divisible by 9.
• The number 91403 is not divisible by 9 because the sum of its digits 9+1+4+0+3=17 is not divisible by 9.

Problem

Find the divisibility of the numbers in following table

Solution