I have worked as an adult educator and with year 9 to 12 maths students. This is an exceptional app for teaching and learning transposition. The free version can be used as the best homework ever. Graphical and clever, it makes the learning fun. A puzzle with carefully introduced tools. More importantly it teaches algebra how students learn algebra, building on their basic understanding of shapes and objects, and how they relate to formulas student's intuitively use (rather than the annoying context teaching). Pros: Beautiful Progressive with simple steps Free Cons: Can't see any