Sudoku is a fun way to improve growth and development. It promotes logical thinking and deductive reasoning skills, decision making, a connection between action and result, better cognitive development, methodical thinking and teaches attention to detail. Features: 8.5" x 11" 40 Easy Puzzles 30 Medium Puzzles 30 Hard Puzzles Product Description: Glossy cover. White paper. Unique gifts for kids under $10 for: Educational gift from grandparents, aunts, uncles, family members and friends. Summer Vacation Gift Back To School Gift etc.