# Free Printable Killer Sudoku Puzzles

At PuzzleAndBrains.com we offer you irresistible Killer Sudoku puzzles. Killer Sudokus are a mix between mathematics (or Kakuro) and Sudoku. Click here for our 6 by 6 Killer puzzles

and click here for the 9 by 9 Killer puzzles. We have the Killer Sudoku math puzzles in

4 difficulty levels: Easy, Medium, Hard and Very hard!

If you want to print and solve our Killer Sudoku logic and math puzzles, click on the 2 images. We have quite a collection of the 6 by 6 and the 9 by 9 number versions! Have fun.

Killer Sudoku are excellent puzzles for leisure and educational purposes as they combine fun, logic and math skills.

## The Basic Rules of Killer Sudoku (aka sumdoku, or samunamupure)

Killer Sudoku puzzles are puzzle that combine elements of mathematic (addition) and sudoku. You could also call teh Killer Sudoku a hybrid version of Sudoku and Kakuro. If you are good at math, the Killer Sudoku is most likely easier to solve than the regular Sudoku puzzles. This depends on your mental arithmetic skills of course.

1. Numbers may only appear once in each row.

Killer Sudoku grids are similar to the regular Sudoku grids. We offer the 6 by 6 and the 9 by 9 versions. In the 6 by 6 grid, you have to fill in the numbers 1 to 6 each once in each row. In the example here you find 2 ones in the top row (in yellow), which is not allowed. The second 1 has to be a ............4 of course

2. Numbers may only appear once in each column.

In this 6 by 6 grid, we have 2 sixes in the last column and this is wrong. We need to fill in the numbers 1 to 6 once in each column. Which 6 is wrong? The 6 in the third position of course. But you figured that our already, because so far the rules are identical to Sudoku (you have to wait for rule number 4 to see the difference between the Killer and Regular puzzle.

3. Numbers may only appear once in each region.

Also in the Killer Sudoku puzzles the grids are divided in regions. The regions are clearly marked by thick black lines! In the 6 by 6 grids, we have 3 by 2 regions (3 times 2 equals 6 numbers) and with the 9 by 9 grid we have 3 by 3 regions (3 times 3 equals 9 numbers). In our example on the left we have 2 sixes (in green) in 1 region. And this is ......................WRONG! Can you figure out which 6 is wrong?

4. The sum of all numbers in a cage must match the small number printed in its corner.

Killer Sudoku grids are not only divided in regions but also in dotted cages. Each cage has a small number printed in it and the numbers you place in a cage must add up to that number (respecting rules 1, 2 and 3 of course). Cages are not confined to single regions and can be part of 2 regions like in our example on the left. The 4 numbers in the shaded cage must add up to 12 (and they do!) but are part of 2 different regions! Challenging, not?

5. You may not use the same numbers in a cage

In our example we have a cage clue number of 12 and a cage that is spread over 2 regions. Both threes in the cage are part of a different region and the total of 5, 3, 3 and 1 would add up to 12. This is, however, not allowed as no similar numbers may be used in a cage (nor region, row and column!). This example is there for showing a wrong solution.

## Strategies to solve Killer Sudoku's

Scan for the 2 digit cage clue numbers: 3, 4, 16 and 17

A great technique for solving Killer Sudoku is using the Kakuro number combinations. As no numbers may be repeated in a cage, the combination for the clue 3 must be 2+1, the clue 4 must be 3+1, the clue 16 must be 9+7 and for the 17 we need a 9+8. Scan your puzzles for these easy starting points. In our example we have put the 1 and 3 in the cage with the 4 clue. Be careful because the order could also be 3 and 1.

Scan for the 3 digit cage clue numbers: 6, 7, 23 and 24

When a cage consists of 3 digits, scan for a 6 clue (1+2+3), a 7 clue (1+2+4), a 23 (6+8+9) and a 24 (7+8+9). Just be careful in which order you place the numbers, as you have to respect the regular Sudoku rules.

4, 5, 6, 7 and even 8 digit cages

In case of a 4 digit case, scan for the numbers 10, 11, 29 and 30. When you encounter a 5 digit cage, look for 15, 16, 34 and 35. In case of a 6 digit cage you need to focus on the 21, 22, 38 and 39 and WHEN you have a 7 digit cage start with the 28, 29, 41 and 42. To make Killer Sudoku cages of 8 digit might sound cruel but they are ou there. Scan for the clue numbers 36 to 44 (all unique combinations)

There are some great websites with advanced solving techniques such as innies, nonets, outies, innie and outie pairs and so on. We prefer making the puzzles than to write endless webpages with solving strategies. Other sites are much better at this: we recommend are Sudocue , Brain Bashers , and Daily Killers

Also, you can use Youtube for some excellent and interesting Killer Sudoku instruction videos. Have a look at the following great videos:

## Online Killer Sudoku Puzzles

If you really insist to play Killer Sudoku online, rather than having those beautiful printed puzzles made by us, we can recommend the following online Killer Sudoku applications: Daily Killer, Killer Online and Sudoku.org. If these applications become and addiction and your eyesight is getting less and less, don't send us a complaint. We have warned you that printed versions (and of course especially ours) are better for the eyes. Not to speak of the radiation of tablets, mobiles and laptops! Please understand that we are a bit cynical here!

If you want to print and solve our Killer Sudoku logic and math puzzles, click on the 2 images. We have quite a collection of the 6 by and the 9 by 9 number versions! Have fun.

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