I'm sure merlyn just wanted you to know that although this works as expected, there are better alternatives. To many, "Matt Wright" is a synonym for "clumsy code that does however do what it's supposed to do" (not to be taken literally: merlyn didn't ask if you went to school with clumsy code :)).
Your approach is directly instructing Perl to do what you want it to do. If you feel comfortable with that, you should do it that way. But often there is some efficiency in both coding and run time to be gained when you use Perl's core functions. In this case, it'd be $number = sprintf '%03d', $number;, which is approximately 2.5 times as fast.
Learn about sprintf. It can be very confusing at first, but the %-notation is easy to get used to.
I very rarely find the need to delte any content. If anything, you should not be ashamed of your (you posted it here) code, but come back 2-3-6 months from now and see if it makes you chuckle (I often revisit ancient code for just this reason ~ if anything me style has changed quite a bit)
Now lokee her'.
All y'all peoples gettin' offended, don't!
Grow som' brains and grow som' brass.
When speakin' expect to be spoken to, even if you' gettin yelled at!! Suck it up.
And finally, fix that short fuse, relax and be nice, you'll live longer.
We all experience such criticism at one point or another, and whether it is warranted or not, it's irrelevant: discussion is good (good for code, and, well, good for pretty much anything -- as a general strategy, discussion rocks).
btw - I ++ed merlyn ~ he wasn't rude ~ i didn't care to vote for you