This book contains 720 SUDOKU puzzles with difficulty varying from easy to hard, which is perfect for every body who loves brain activity games. There are plenty of puzzles for you to play and relax your brain: 240 easy, 240 medium, 240 hard puzzles. Instructions and solving techniques for beginners are included in the introduction. Answer keys are provided at the back of the book. Doing Sudoku puzzles improves memory and doing crosswords improves verbal fluency and word games are great for learning vocabulary, researchers have found.
