Divisibility Rule for 9

If you divide a number by 9 and you get a whole number as an answer (quotient), then that number is divisible by 9.

Instead of simply dividing your number by 9 to see if you get a whole number, you can use what we call the Divisibility Rule for 9.

The Divisibility Rule for 9 is used to determine if a number is divisible by 9. You can also call it the test of divisibility for 9.

A number is divisible by 9 if the sum of its digits is divisible by 9.

For example, with 123,456, the sum of its digits is 1 + 2 + 3 + 4 + 5 + 6 = 21. Since 21 is not divisible by 9, neither is 123,456.

However, in 156,789, the sum of the digits is 1 + 5 + 6 + 7 + 8 + 9 = 36. Since 36 is divisible by 9, 123,456 is also divisible by 9.

Divisibility Rule for 10
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Divisibility Rules
Here is a list of all our Divisibility Rules.