Killer Sudoku is a fun and addicting logic puzzle game that combines Sudoku with an addition math game. Killer Sudoku is a fun way for kids and adults to practice addition facts. In this book, you do not need to wade through tons of easy Killer Sudoku 10x10 puzzles before getting to the real brain teasers. Once you pick up this book, you won't be able to put it back down. You have been warned! Killer Sudoku 10x10 - Hard is a collection of 267 puzzles: 216 hard Killer Sudoku 10x10 puzzles 51 extra logic puzzles I guarantee that every logic puzzle in this Killer Sudoku puzzle book has been carefully checked to ensure that each puzzle has only 1 solution. None of the puzzles in this book will appear in any of the other PuzzleBooks.net books. Killer Sudoku is also known as Sums Sudoku, Sumdoku, Sum Doku, Addoku, Killer Su Doku, Samunamupure, Kikagaku Nampure, Samu Nanpure, Sums Number Place.