3 Divisibilty Trick

In this week's math trick, we learn how to tell if a number is divisible by 3 while skipping the division! 

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It's easy to tell if a number is divisible by 3!  Add all the digits of the number you are trying to divide by 3.  If the digits add to a multiple of 3, then the number is divisible by 3!  In our example, we use 87.

8+7=15

and 15 is a multiple of 3

therefore, 87 is divisible by 3!

Ready for some more? Try out the practice problems below!