Fantastic
This is educational software at its very best: clever, beautiful, and enjoyable. The hand-drawn UI is really charming, and the behaviors (movement and sound) build on it well. The ability to choose different numbering systems (dice, roman nums, braille, tallies, binary, hex, etc.) suggests a deep lesson, that math is both true *and* cultural. And the range of problems - and problem-solving techniques it invites - is impressive. There isn't a patronizing pixel in this app. And, best of all, it made me curious about the dev's other apps - some of which are even more interesting.