App Review: Algebra Touch

I just came along a great app for the middle school math teacher. Algebra Touch is great way to help students learning properties of math. It's a little skill and drill-ish, but offers some descriptions behind number operations.

For example, when I work with negative numbers, some of my students wonder why you might add or subtract numbers in a give situation. Also, they wonder why some things cancel, and some don't. Why are these "like terms" and these "unlike terms"?

The drop down menu of skills is great and already I've utilized the app for students that struggle with a particular skill set.