Divisibility: The ability to divide without a remainder

Knowing divisibility rules will help in math.  A key reason for knowing  divisibility rules is to help work with fractions, ratios, and probability.   Knowing if something can be   divided by a number helps us figure out factors, and common factors needed to reduce fractions, ratios and probabilities.  So, let's look at the rules:


It is an even number (ends in 2,4,6,8, or 0)

The sum of the digits of the number is divisible by 3

The number formed by the last 2 digits is divisible by 4

The number ends in 0 or 5

It is even and the sum of its digits is divisible by 3

(no simple rule)

The number formed by the last 3 digits is divisible by 8

The sum of the digits is divisible by 9

The number ends in 0

Check Your Understanding

Check your skill at identifying divisibility by numbers:

  1. Enter number 1 between 2 and 99999.
  2. Enter number 2 as 2,3,4,5,6, or 10.
  3. Decide whether you believe the 'number 1' is divisible by 'number 2'.
  4. Click the button "Check" and check your answer.