From the original publisher of daily sudokus in the U. S., USA TODAY presents 200 all-new sudoku puzzle challenges in 5 difficulty levels. USA TODAY Sudoku Super Challenge is a collection featuring 200 sudoku puzzles in five difficulty levels from USA TODAY—the nation's no. 1 newspaper. Features include:Introductory how-to section200 9 x 9 sudoku puzzlesComprehensive answer key | USA TODAY Sudoku Super Challenge by USA USA TODAY, Paperback | Indigo Chapters