Killer Sudoku
The ultimate hybrid of math and logic.
The Killer Rule
In Killer Sudoku, normal Sudoku rules apply, but the grid is also divided into "cages" (groups of cells surrounded by dashed lines).
The Rule: The sum of the digits inside a cage must equal the small number in the top-left corner of the cage. Also, digits CANNOT repeat within a single cage.
The Rule of 45
Because the digits 1 through 9 must appear exactly once in every row, column, and 3x3 block, the sum of those 9 digits is always 45 (1+2+3+4+5+6+7+8+9 = 45).
If you have cages that cover exactly one block except for a single cell outside the block, you can use the Rule of 45 to deduce the exact value of that extra cell!
💡 Easy Practice: We have pre-filled almost the entire board for you! To solve this challenge, simply look at the dashed cages. Make sure the missing numbers you place add up exactly to the small number printed in the top-left corner of the cage.