Making a counter from 0-9 that then goes back to 0 again, not10?

Hi All

I would like to teach my students how to use a piece of equipment which has 3 digits that can be adjusted. I would like to make a storyline file so that the students press a button which advances the numbers from a specified range. So for example, the top numbers are either 0,1 or 2. If they select the button, rather than becoming 3, the value needs to go back to 0.

Can anyone tell me how this can be done?

Many thanks in advance

Maurizio