A multiple of 3 is any number for which the sum of all its integers is divisible by 3. For example, 12 is a multiple of three, for 1 + 2 (the integers of "12") equals a number divisible by 3.

As is the number 519 (5 + 1 + 9 = 15). You can also take this one step further, as the integers of "15" add up to a number divisible by 3 (1 + 5 = 6).

As is the number 4,269,345 (4 + 2 + 6 + 9 + 3 + 4 + 5 = 33). Then, add the integers of 33 (3 + 3 = 6).

It's one of those great little tricks that makes mathematics just a little easier to use.

Multiples of three cannot be exhaustively listed, they are all the integers that are exactly divisible by three.

Therefore, multiples of 3 = 3*n

Where n = 1,2,3,4,5,6,...................................

Keep adding 3's--6, 9, 12, 15, 18, 21, and so on. They are multiples, because when you add on a 3, you also get that answer by multiplying a 3 by 2, then 3, then 4, then 5, 6, 7, and so on....

...Any number divisible evenly by three is a multiple of three. For example ; 3, 6, 9, 12, 15...continued in this manner indefinitely. The same principle applies to all numbers.

...