Killer Sudoku: FILE No. 25-0501

KILLER SUDOKU: FILE No. 25-0501 is a challenging puzzle collection designed for serious Sudoku fans who are ready to push their logic and math skills to the next level. Featuring 80 carefully crafted Killer Sudoku puzzles-with difficulty levels ranging from medium to extreme-this book is built to test your mind and keep you thinking. Killer Sudoku takes classic Sudoku to a new level by adding the challenge of mental arithmetic. In addition to placing numbers without repeats in rows, columns...