This is a great use of power point! I enjoyed it and was humbled by my lack of math skills. I liked the examples that asked you what to do next and adding a few more of these along with some more problems and this would be outstanding.
These not a lot you can do with power point beyond what you have already done. This lesson would be perfect for Camtasia Studio. You could recorded you lessons and quiz throughout the video. This would also allow you to narrate the video.