Divisibility Rule for 12
If you divide a number by 12 and you get a whole number as an answer (quotient), then that number is divisible by 12.
Instead of simply dividing your number by 12 to see if you get a whole number, you can use what we call the Divisibility Rule for 12.
The Divisibility Rule for 12 is used to determine if a number is divisible by 12. You can also call it the test of divisibility for 12.
A number is divisible by 12 if the number formed by the last two digits in the number is divisible by 4 AND the sum of the digits in the number is divisible by 3.
For example, for 123,456 the last two digits (56) is divisible by 4, AND 1 + 2 + 3 + 4 + 5 + 6 = 21. 21 is divisible by 3. Thus, 123,456 is divisible by 12.
However, 123,458 is not divisible by 12 for two reasons: The last two digits (58) is not divisible by 4 and 1 + 2 + 3 + 4 + 5 + 8 = 23 and 23 is not divisible by 3.
Remember, both conditions must be met for the number to be divisible by 12.