What are some multiples of 3?

Some multiples of 3 are 6, 9, 12, 21, 300, -3 and -15. All numbers that are equal to 3 multiplied by an integer (a whole number) are multiples of 3.

There are infinitely many multiples of 3. One interesting fact about multiples of 3 is that the sum of the digits of each multiple is always equal to either 3, 6, or 9. All alternative multiples of 3, starting from 6 and including 12, 18, 24 and so on, are also multiples of 6. Some multiples of 3 are also multiples of 9, and the sum of the digits of each of these multiples is always equal to 9.