Can you crack Killer Sudoku's mathematical twist? The objective of Sudoku is to fill each row, column and sub-grid with exactly one of each number from 1-9. In Killer Sudoku, the digits in each inner ...
Fill the grid so that every row, every column and every 3x3 box contains the numbers 1 to 9. To see the completed puzzle, buy the next issue of the Guardian (for puzzles published Monday to Thursday).