To match a number, this is what you should use:
[1-9][0-9]*
That way, it eliminates leading zeroes, and the rule can be read as "any number from 1 to 9, followed by any amount of numbers from 0 to 9."
Or you could do this for numbers from 0 to 999 (which is what I thought you were trying to get):
[1-9][0-9]{0,2}