How many positive multiples of 3 less than 1000 use only the digits 2 and/or 4 and/or 6?

So there are 3 ways to make a number divisable by 6 with these numbers.

6

2 and 4

2, 4, and 6

So there is 1 one-digit mutiple. (1!)

There are 2 two-digit mutiples. (2!)

And there are 6 three-digit mutiples. (3!)

So you get 9.

(6, 24, 42, 66, 222, 246, 264, 426, 444, 462, 624, 642, 666)>>Total = 13 such numbers.