Lesson 2: Divisibility Tests

Property

A number is a multiple of $n$ if it is the product of a counting number and $n$.
If a number $m$ is a multiple of $n$, then $m$ is divisible by $n$.

Examples

Property

If a number $m$ is a multiple of $n$, then we say that $m$ is divisible by $n$. We can use divisibility tests as shortcuts.
A number is divisible by:

• 2 if the last digit is 0, 2, 4, 6, or 8
• 3 if the sum of the digits is divisible by 3
• 4 if the last two digits form a number divisible by 4
• 5 if the last digit is 5 or 0
• 9 if the sum of the digits is divisible by 9
• 10 if the last digit is 0

Examples