Killer Sudoku (also called Sum Sudoku) are a kind of hybrid puzzle that combine the best features of Sudoku and Kakuro (cross-sum) puzzles. Like a regular Sudoku the rows columns and 3x3 blocks contain the digits 1 thru 9. In addition the dotted lines indicate areas called cages which also contain a set of non-repeating digits. If you add up the digits in a cage you get the sum shown in its clue. Happy puzzling!ContainsGlossy premium cover8.5 x 11 size top quality paper200 killer sudoku puzzlesS