This fantastic inconspicuous book contains as many as 200 puzzles with 4 levels of difficulty. From easy to medium to very difficult. At the end of each level, there are solutions. Each level starts with the appropriate sized dog as the patron of that level. Sudoku trains logical thinking and memory. That is why it is worth making children interested in this game. Fortunately, there is no need to start with a difficult level of the game. Easy levels already allow you to practice basic skills. After that, you can increase the difficulty of the game and start solving sudoku on time. Sudoku is a very good solution for the elderly . Contrary to appearances, just solving crosswords according to research is not enough to act prophylactically against Alzheimer's disease. Sudoku is much more fun to develop in this respect, as it requires more than just schematic solutions, especially at higher difficulty levels. Adults too should train their minds to maintain good memory. ◆ 200 puzzles ◆ 4 difficulty levels ◆ canine patron of each level Perfect for personal use. A great gift for a loved one. Click the "Add to Cart" button to order.