Hard Sudoku

HARD SUDOKU FOR PRO - 240 HARD puzzles for SUDOKU - Large characters - 4 puzzles per page - 60 pages of sudoku exercises plus 60 pages of solutions (total: 120 pages) SUDOKU puzzles are known to reduce anxiety, Great for memory training, great fun and easy to learn Even if you have absolutely no math skills. HOW TO DO? Simply enter the numbers 1 to 9 once in each row, column and box to solve each sudoku