What are all the multiplies of 3?

Answer 1

It would be impossible to name all of the multiples of three, as there are an infinite number of them. Consider, take the number sequence:

1, 2, 3, ... , ∞

If you multiply each of those numbers by three, you would get:

3, 6, 9, ... , ∞

So they could never be transcribed as a limited set. You could however represent them as a set. That would be:

{3x | x ∈ I}