Killer Sudoku Online - Free Math Puzzle Games
Looking for something more challenging than regular sudoku? Killer sudoku combines everything you love about classic sudoku with an extra mathematical twist. In addition to following standard sudoku rules, cells are grouped into cages that must add up to specific target sums. It's like sudoku and arithmetic had a puzzle baby. Perfect for players who want to exercise both their logic and math skills at the same time.
What is Killer Sudoku?
Killer sudoku takes the classic 9×9 grid puzzle and adds a mathematical layer. Cells are grouped into outlined areas called cages, and each cage has a target sum. Your job is to fill the grid so that numbers in each cage add up to that target, all while following traditional sudoku rules. No number can repeat in a row, column, or 3×3 box. This variant requires both logical reasoning and basic arithmetic—making it twice the fun for puzzle enthusiasts.
How to Play Killer Sudoku
Killer sudoku follows all the standard sudoku rules you already know, plus one important addition:
- Every row, column, and 3×3 box must contain the digits 1-9 exactly once (standard sudoku rules)
- Numbers within each cage must add up to the target sum shown
- Numbers can't repeat within a single cage (unless that cage spans multiple rows, columns, or boxes)
- Use the cage sums as clues to figure out which number combinations are possible
Killer Sudoku Solving Tips
Here are some strategies that will help you master killer sudoku:
Tackle Small Cages First Small cages with just 2 or 3 cells have very limited number combinations. Work out all the possible ways to reach the target sum, then eliminate any combinations that would break sudoku rules. This approach often reveals exactly which numbers must go where.
Use Sum Constraints to Your Advantage Some cage sums have only one possible combination. For example, a 2-cell cage with sum 3 must be 1+2. A 9-cell cage with sum 45 must contain all digits 1-9. These constraints are powerful tools for narrowing down possibilities.
Balance Math and Logic Remember that both the cage sum and sudoku rules must be satisfied. A number combination that works mathematically might still be impossible if it violates row, column, or box constraints. Always check both the math and the sudoku rules before placing numbers.
Ready to combine logic and math? Start playing free killer sudoku puzzles online and see how your problem-solving skills stack up!