in reply to Functions in Perl
In the general sense, yes, your solution to the exercise is correct and functional. Many would suggest various tweaks and adjustments for the sake of clarity and/or efficiency, but overall it's good, and as a beginner you seem to be on a good track.
However, I would recommend moving to Learning Perl sooner rather than later. I have nothing against Laura Lemay, but most of the "Learn * in 21 Days" books focus too little on understanding the core topic itself, and leave the reader with limited ability to adapt and improvise.