Pre-Algebra

Divisibility Rules

Divisibility Rules for 2

1.     All even numbers are divisible by 2. E.g., all numbers ending in 0,2,4,6 or 8.

Ex.228

 Divisibility Rules for 3

1.  Add up all the digits in the number.

2.  Find out what the sum is. If the sum is divisible by 3, so is the number.

Ex.3345

Divisibility Rules for 4

1.     The last two digits are divisible by 4.

Ex. 812

Divisibility Rules for 5

1.     Numbers ending in a 5 or a 0 are always divisible by 5.

Ex. 500

Divisibility Rules for 6

1.     The number is divisible by both 2 and 3.

Ex. 114

Divisibility Rules for 9

1.   Add up all the digits in the number.

2.  Find out what the sum is. If the sum is divisible by 9, so is the number.

Ex. 9432