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Divisibility tests

4 videos
1 skill
Whether you are trying to impress your dog's friends (who are obsessed with figuring out number divisibility) or quickly factor a number, it can be very useful to tell whether a number is divisible by another. This tutorial walks through some of the more standard divisibility methods and describes why they work.

Divisibility tests for 2, 3, 4, 5, 6, 9, 10

VIDEO 6:33 minutes
Worked example of basic divisibility tests

Recognizing divisibility

VIDEO 6:26 minutes
Recognizing Divisibility

The why of the 3 divisibility rule

VIDEO 5:03 minutes
Why you can add the digits to see if something is divisible by 3

The why of the 9 divisibility rule

VIDEO 5:08 minutes
Why you can test divisibility by 9 by just adding the digits

Divisibility tests

PRACTICE PROBLEMS