KenKen is a number puzzle that combines the logic of Sudoku with elementary arithmetic. Master three simple rules and you can solve any puzzle. You may also know this puzzle as Mathdoku or CalcuDoku — same rules, different name.
A KenKen puzzle is played on an N×N grid — 3×3 for beginners, up to 9×9 for experts. Your goal is to fill every cell with a number from 1 to N. A 4×4 grid uses the numbers 1, 2, 3, and 4.
Every number from 1 to N must appear exactly once in each row, and exactly once in each column. No repeats — just like Sudoku. This constraint alone lets you eliminate many possibilities.
Each of 1–4 appears once per row
Each of 1–4 appears once per column
Groups of cells outlined with a bold border are called "cages." Each cage has a small label in its top-left corner: a target number and an arithmetic operation (like "6+" or "3−"). The numbers you place in that cage must produce the target when you apply the operation.
Cages use one of four arithmetic operations. Each operation has a simple rule about how the numbers in its cells must relate to the target.
The numbers in the cage must add up to the target.
3 + 4 = 7The difference between the two numbers equals the target. Order doesn't matter — largest minus smallest.
4 − 2 = 2The numbers in the cage multiply together to reach the target.
3 × 4 = 12The larger number divided by the smaller equals the target. Always two cells.
6 ÷ 3 = 2A cage containing only one cell uses the "=" label and no operation — just place that exact number directly in the cell. Single-cell cages are a free gift: they immediately tell you a number without any calculation.
Let's walk through solving a real 4×4 puzzle step by step. Click Next to apply each rule in turn.
Step through a complete 4×4 solve
Here is a 4×4 KenKen puzzle. Every cell needs a number from 1 to 4. Each row and column must contain each number exactly once, and every cage must satisfy its arithmetic rule.
Start with an easy 4×4 puzzle and work your way up to the 9×9 expert grids.