My 3 yo adores this app and has learned so much. As an educator I'm excited that it is much more then memorizing facts or basic recall- it really gets to the heart of what makes a number a number. So great. Anyway, I was incredibly disappointed when I pulled out my Cuisenaire rods and the colors are not the same! It seemed like such an obvious extension, yet my son was so confused by the color change when we tried to do puzzles together. A real missed opportunity there.