Fantastic! I would pay more for additional puzzles.
This game is beloved by my math loving son, who learned algebra with a great deal of help through this app. I wish there were 10x as many puzzles! There's enough puzzles to introduce each concept (and it's really broken down to tiny incremental conceptual steps brilliantly) but not enough to get to mastery once all the concepts are introduced. I'd happily pay for additional puzzle packs beyond the existing ten levels! Just give us more exercises!