Divisibility Rules Overview

This is a quick overview of the divisibility rules.

1- Every number is divisible by 1.

2- If the last digit is an even number.

3- The sum of the digits is divisible by 3.

4- If the number is divisible by 2 at least twice.

5- If the number ends in 5 or 0.

6- If the number is divisible by 2 and 3.

7- (No rule.)

8- If the number is divisible by 2 three times

(I looked up "thrice" in an online dictionary and it's an actual word meaning three times. If you don't believe me, look it up yourself.)

9- If the sum of the digits is divisible by 9.

10- If the number ends in 0.

0- It is impossible to split a number into zero groups, even decimals can't be split into nothing.


Can you find out if a number like this: 2,617,628,132
is divisible by 4 and/or 8 mentally easily? If so create a divisibility rule for 7.