Killer Sudoku Puzzles to Drive You Mad! Vol. 2

If you solved all the puzzles in the first book and are ready for more, this is the book for you. The Killer Sudoku puzzles in this volume start at level five (medium), and go up to level eight (hard). Killer Sudoku offers a twist on normal Sudoku. You still write numbers 1-9 in different boxes, but this time you use simple math to figure out where to write each number. Inside you'll find 104 Killer Sudoku puzzles in four different levels of increasing difficulty. Good luck! Killer Sudoku is also calld Sumdoku, Addoku, and Samunamupure. (If you're new to Killer Sudoku, you might want to start with volume one in this series. The puzzles in that book are all beginner to medium level.)