Volume 8 of the most popular series of books with difficult Killer Sudoku puzzles - now even more fun Contents: 100 Killer Sudoku 10 Killer Sudoku with all operators (+, -, *, /) 10 Frame Killer Sudoku and 30 ZERO Killer Sudoku (blank cages) Difficulty levels are COOL-THINKER-BRAIN-IQ. The easiest level (EASY) has been removed A majority of puzzles are THINKER and BRAIN, with lots of IQs, too. Zero Killer Sudoku puzzles are mostly IQs, of course. All puzzles in this book are NEW. There is also a special gift at the very end of the book Are you ready for this?