- Definition
A divisibility rule is a quick trick to check if one number can be divided evenly by another without actually doing the long division. For example, if a number ends in a 0 or 5, you know it can be divided by 5.
Using the rule for 5, we know 345 is divisible by 5 because its last digit is a 5.
How to teach this in 30 seconds
Try this analogy: A divisibility rule is like a secret shortcut in a video game that helps you solve a puzzle faster.
Ask your child: Without dividing, how can you tell if 120 can be shared by 10 people?
Common mix-up: Kids might think the only way to check for divisibility is to perform the full division calculation. These rules are clever shortcuts that let you check just by looking at the digits.
Examples
- We know 78 is divisible by 2 because its last digit, 8, is an even number.
- To check if 123 is divisible by 3, we add its digits (1+2+3=6), and since 6 is divisible by 3, the number is too.
- Any number ending in 0, like 450, is divisible by 10.
divisibility rule is a term used in Ontario’s Kindergarten to Grade 8 curriculum.
Where this shows up
The descriptions on this page are SmartStudy’s own original, plain-language writing — not the Ministry’s wording. They are aligned to the Ontario Curriculum, © King’s Printer for Ontario. For the Ministry’s official wording, see the source link below. SmartStudy is an independent service and is not affiliated with, endorsed by, or sponsored by the Government of Ontario or the Ministry of Education. Ontario Curriculum and Resources ↗
