Killer Sudoku (Free Printable PDF)
A killer sudoku blends the classic nine-by-nine grid with a tasty extra twist. The grid is divided into dashed groups called cages, and a small number in the corner of each cage tells you what its digits must add up to. As well as the usual rule — every row, column, and three-by-three box holds the digits one to nine exactly once — no digit may repeat inside a cage. There are very few starting numbers, so the cage sums, not the givens, do the work, and every puzzle still has exactly one logical solution. Play it on the screen, where the cages are drawn for you and repeats are flagged, or download a clean, printable PDF with the cages, the sums, and a full answer key.
How to make it
- Read the small sum in the corner of each dashed cage.
- Fill the grid so every row, column, and 3x3 box has the digits 1 to 9.
- Within each cage, make the digits add up to its sum and never repeat a digit.
- Solve it on screen, or download the printable PDF with the answer key.
Frequently asked questions
What are the cages and the little corner numbers?
Each dashed group is a cage, and its corner number is the total its digits must add up to, with no digit repeated inside the cage.
Can a digit repeat inside a cage?
No. On top of the usual sudoku rules, the digits within a single cage must all be different, even though they add to the cage sum.
Why are there so few starting numbers?
In a killer the cage sums provide the constraints, so it needs few or no givens and still has exactly one logical solution.
Is the killer sudoku free with the answer key?
Yes, generating, playing, and the printable PDF with its cages and full answer key are all completely free.