Algebra Lesson on Factoring

This is just the type of lesson I love: a manipulative basis to understand a somewhat hard concept. In my CPM book, this is the only way the lesson is presented. I love algebra tiles because it gives a true basis for experimentation for students who struggle with the notation and numerical sense of algebra, while also offering the advanced students a model to ponder and wonder about.

http://mathforum.org/alejandre/algfac.html