Play KenKen Pro Online: The Ultimate Math & Logic Puzzle

If you love the grid-filling logic of Sudoku but want to add a fresh layer of mathematical challenge, it is time to try KenKen Pro.

Also known around the world as Mathdoku or Calcudoku, this incredibly popular puzzle strips away the traditional 3×3 Sudoku boxes and replaces them with heavy-outlined “cages.” To win, you will need to use your spatial deduction skills combined with basic addition, subtraction, multiplication, and division.

Whether you want a quick mental warmup on our 4×4 Easy mode or a serious brain-bender on our 6×6 Hard mode, Puzzrs has you covered. Choose your grid size below, flex your math muscles, and conquer the board!

How to Play KenKen (Rules for Beginners)

The rules of KenKen are a perfect blend of spatial logic and arithmetic.

1. No Repeats in Rows or Columns: Depending on your difficulty, the grid will be 4×4, 5×5, or 6×6. You must fill every row and column with the numbers 1 through the grid size (e.g., 1 to 4 on Easy) exactly once.
2. Follow the Cages: The grid is divided into heavily outlined blocks called “cages.”
3. Do the Math: The top-left corner of each cage has a target number and a math symbol (like 12× or 3-). The numbers you put inside that cage must equal the target number when combined using the specified math operation.
4. Repeats Are Allowed Inside Cages: Unlike Killer Sudoku, you can use the same number twice inside a single cage, as long as the numbers do not share the same row or column!

(To play the game above, click an empty square to select it, then use the dynamic on-screen number pad or your keyboard to type your guess. Completed numbers will automatically gray out on the numpad!)

Winning Strategies: How to Solve KenKen Puzzles

You do not need to be a math genius to play KenKen; you just need a solid strategy. Here are the best ways to solve the board quickly:

1. The “Freebies” (Single Squares)

Always scan the board before you start. If you see a cage that is only one single square, it will not have a math operation next to it—just a plain number (like 3). That is a freebie! Fill it in immediately to get your puzzle started.

2. Hunt for Prime Numbers & Extremes

Look for multiplication cages with large prime numbers or extreme targets. For example, if you are playing on a 5×5 grid and see a cage that says 20× spread across two squares, the only possible combination is 4 and 5. If you see 3- in two squares on a 4×4 grid, it must be 1 and 4!

3. The “Process of Elimination”

Because you cannot repeat a number in a row or column, completing one cage often unlocks another. If a row already contains a 1, 2, and 4, and you have an empty square in a division cage that says 2÷, you instantly know that empty square must be the 3 (and the other number in the cage must be a 6)!

Looking for More Logic Puzzles?

If you prefer your puzzles to focus heavily on addition without the multiplication and division, check out our highly popular Killer Sudoku Pro. If you want a break from math entirely to focus on pure spatial deduction, dive into Sudoku Pro!