0
NEVER Divide by 0
1
Everything is divisible by 1
2
If it is even it is divisible by 2
3
Add all digits if the sum is divisible by 3 so is the number
4
Take the last 2 digits if it is divisible by 4 you have got your answer
5
If the last digit off the number is 0 or 5
6
If the number is divisible by both 3 and 2
8
If the last 3 digits make a number divisible by 8
9
Add all digits if the sum is divisible by 9 so is the number
10
If the number ends in 0
12
If the number is divisible by both 3 and 4