Well, I looked into writing code in VBA and I actually got it to work! You mentioned change events, so I did a search and came up with this thread that helped a lot: http://www.excelforum.com/excel-general/686940-cell1-cell2-and-cell2-cell1.html

So I got it working. Everything is good. I transfer it to my tablet, only to find out THEN that the free excel app I'm using (Kingsoft Office) doesn't support VBA (well, for $60 bucks it does), rendering this little experiment useless! lol Looks like I'll be going with your first suggestion of keeping it simple. At the very least I learned something new. Thank you for all your help.