Entertain and challenge your brain with these normal to hard 9x9 sudoku puzzles!A great way for relaxing, stress relief and having fun!Features: - 4 puzzles per page;- 960 9x9 total puzzles;- 320 normal, 320 medium & 320 hard puzzles;- Solutions included after each section;- Great for kids, teens, adults & seniors;- Hours of mind-sharpening fun;- Perfect size, 8.5" x 11" (22 x 28 cm);- Flexible premium paperback;- Printed on high-quality white paper;Perfect gift for sudoku, activity and puzzle book lovers!