12 is a multiple of 3 and 4. Therefore, the multiples of 12 must be divisible by 3 and 4. We have learned that
If the sum of the digits of a number is a multiple of 3, then the number must also a multiple of 3.and also
If the first two digits of a number is a multiple of 4, then the number if a multiple of 4.
We can use these two rules to tell if a number is a multiple of 12.
For example:
Is 762288 a multiple of 12?
The sum of the digit:
7 + 6 + 2 + 2 + 8 + 8 = 33
33 is divisible by 3, hence 762288 is a multiple of 3.
The first two digits of 762288 is 88, and 88 is a multiple of 4, hence 762288 is a multiple of 4.
Since 762288 is a multiple of 3 and 4, hence it must also a multiple of 12.
Let's see another example:
Is 7365436 divisible by 12?
The first two digits is 36, and 36 is a multiple of 4, hence 7365436 is a multiple of 4.
The sum of the digit:
7 + 3 + 6 + 5 + 4 + 3 + 6 = 34
34 is not divisible by 3, hence 765436 is not a multiple of 3.
Therefore 7365436 is not divisible by 12.
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