[Bored chemist]

You cheated by counting thumbs as fingers!

It's hardly "cheating" when everyone does it.

[Petrochemicals]

You cheated by counting thumbs as fingers!

Because you need a double zero it is impossible.

This might amuse those of a mathematical persuasion.

We have a novelty advent calendar. For anyone brought up in a different faith, it counts down the days from 1 to 25 December. Ours consists of two numbered wooden cubes which you can rearrange to display every integer from 25  to zero.

What numbers are painted on each cube? 

I believe it is possible with roman numerals.

1a) no face, X, V, IX, XX, XV
2a)I,II, III, IV, V, X
3
I could be wrong!

You can actually do away with the "V" on the 2a) cube, as long as you substitute it for a blank face. If you are willing to hide the one,

1a)x,v, xx, xv, ix
2a) I, ii, iii,iv, x

[alancalverd (OP)]

Oh no you can't.

Exercise works pretty well, though I'm not allowed to advertise the company I work with either!