Sudoku Puzzle Book for Adults.* The book contains 716 Sudoku puzzles (236 Easy+ 240 Hard + 240 Very Hard+Answers ). * 4 puzzles per page. * It will be easier to work on the puzzles. * All riddles have only 1 solution. * The font size is correct, you will not have to strain your eyes when solving puzzles. * High quality paper and print (all puzzles read well). * Your task is to fill each row, column and irregular shape with the numbers 1 - 9.