Salient Features of Crazy Sudoku 16X16 Puzzle Book: Book Size Dimensions : 8.5"X11" No. of Puzzles : 300 (150 Easy-Medium, 150 Hard) Difficulty Level : Easy-Medium-Hard Suitable for : This Sudoku Puzzle Book Variety is actually suitable for anyone who knows the basics of how to solve sudoku puzzles such as Sudoku for Beginners, Experts, Advanced Players, Elderly, Inmates, Moms, Old People, Seniors, Young Adults, Teens and Teenagers Specialty : Contains Sudoku One Puzzle per Page (So, it becomes very comfortable for the eyes of the player to focus on just one at a time while playing. A perfect clutter free puzzle solving experience that customers will definitely enjoy.) About : 16X16 Sudoku contains a regular 16X16 puzzle that has to be solved by filling in the numbers from 1-16 and that in turn makes solving the puzzle a little bit challenging. Benefits of Playing Sudoku Puzzle Games : 1. It helps boost logical thinking. 2. It may improve memory and recall. 3. It may help slow down the negative impact of Alzheimer's Disease and Dementia.(N.B.: However, Playing Sudoku should Not be considered as a Medical Treatment Alternative for any physical or mental illnesses. It is just a form of mental/brain exercise and NOT a treatment.) 4. It may help to develop quick thinking skills & may improve concentration. 5. It may help reduce anxiety and stress. 6. It is a great way to improve a child's problem solving skills. 7. It promotes a healthy mindset.