When you buy this book you get an electronic version (PDF file) of the interior of this book. 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 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! Only 1 Killer Sudoku puzzle per page, with lots of white space for scribbling. Killer Sudoku 9x9 Large Print - Hard is a collection of 270 puzzles: 216 hard Killer Sudoku 9x9 puzzles 54 extra logic puzzles The goal of Killer Sudoku is to fill in the empty cells, one number in each, so that each column, row, and region contains each number exactly once. The sum of all numbers in a cage (indicated by the dashed lines) must match the small number printed in its corner. No number can be repeated within a cage. 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.