Algebra Tiles Animated Presentation

This is a powerpoint presentation I made to help explain how to use algebra tiles to solve equations.
Each slide shows the setup of the equation as well as animations of the on-screen tiles to go along with each step of solving it.

To be honest I don't like using algebra tiles myself. I recognize that there are a lot of good things about them, but I've found that I like using undo tables to teach solving equations. If I was still trying to work with algebra tiles I would probably go back and streamline this presentation a bit and make something more interesting for when negative and positive units cancel out. But it isn't too bad as it is. :)

edit 12/15/11
I corrected a few errors in the last couple of slides. I apologize if you already used it and found out about them the hard way. If there are any other issues, please let me know!