This is one of those rare math books that actually works—it takes intimidating concepts and makes them feel like magic tricks instead of torture. The dream framework is clever, the Number Devil character is endearing, and the progression from simple to complex feels natural.

That said, it's not for every kid. If your child struggles with reading stamina or gets frustrated by abstract thinking, this might not land. It's also not a rip-roaring adventure; it's more meditative and idea-driven. But for the right kid—especially one who's decided math is boring or hard—this can be genuinely transformative.

The book is from 2000 (originally 1997 in German), so the framing feels a bit old-school, but math doesn't age the way pop culture does. The concepts are just as relevant today, and the enthusiasm is infectious. If you've got a 4th-6th grader who needs a math confidence boost or just loves patterns and puzzles, this is a solid pick.