It contains a collection of 120 classic Sudoku problems, expertly designed and graded: 20 Easy, 40 Medium and 60 Hard puzzles. That makes it suitable for all addicts of this brain-bashing game, kids and adults alike. We've had your entertainment and convenience in mind when designing this book and thought about the small details which make a difference: 1 problem per page and solutions at the end of the levels Larger font and better quality paper than newspapers and magazines - easy to write on without worry of bleed through Problem levels has been expertly assessed for consistency. This book with hours of fun inside also makes a great gift!