Quick tests for Divisibility

Number 2

If the number is even it is always divisible by 2.

Number 3

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

Example: 123 gives 1+2+3= 6 which is divisible by 3 therefore 123 is divisible by 3.

Number 4

If the last two digits of a number is divisible by 4 then the whole number is divisible by 4.

Example: 724 so 24 is divisible by 4 so 724 is divisible by 4 = 181

Number 5

If the last digit is a 5 or a 0 then the whole number is divisible by 5.

Number 6

If the number is divisible by 2 and 3 then the whole number is divisible by 6.

Example: 924 So 924 digits add to 15 and 13 is divisible by 3 and 924 is an even number therefore 924 is divisible by 6 = 154

Number 8

If the last three digits are divisible by 8 then the whole number is divisible by 8.

Example: 412,816 so 816 is divisible by 8 so 412,816 is divisible by 8 =51,602

Number 9

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

Example: 5211 gives 5+2+1+1= 9 Therefore 5211 is divisible by 9 = 579

Number 10

If the number ends in 0 then the whole number is divisible by 10.

Unfortunattely there is no easy rules for Number 7 that I know of! But, if all the others fail, try 7!