Attention, puzzle lovers! Prepare yourself for THE popular new way to show off your skills. Easy to learn, tough to master, each numerical Su Doku grid looks like an innocent crossword puzzle but acts like a killer video game. No math required -- just a sharpened pencil and an urge to conquer.Here you'll find everything you need to become the first Su Doku super-genius on your block: 100 fun number puzzles, seven top-secret tricks (shh!), and the number-one most challenging Su Doku puzzle ever!