Free Printable Calcudoku — KenKen / Mathdoku Generator

Calcudoku — also published commercially as KenKen and Mathdoku — combines the grid logic of sudoku with arithmetic. The puzzle uses a square grid (6×6 or 9×9) divided into cages — irregular groups of cells outlined with a thick border. Each cage displays a target number and an operation (+ − × ÷).

• Every row must contain each digit exactly once.
• Every column must contain each digit exactly once.
• The digits inside each cage must produce the cage's target when the stated operation is applied to them.
• A digit may repeat within a cage — provided it does not appear twice in the same row or column.

For subtraction or division cages with more than two cells, arrange the cage's digits from largest to smallest before applying the operation (e.g., a 1− cage containing 4, 2, 1 reads 4 − 2 − 1 = 1). A cage of a single cell simply shows that cell's value directly.

1. Choose a Puzzle size — 6×6 for a shorter puzzle, 9×9 for a full challenge.
2. Choose a Level — controls how many cells are pre-filled with their solved value.
3. A new puzzle loads automatically. Click Create for a fresh puzzle at the same settings.
4. Click Show Solution to reveal all values and verify the puzzle.
5. Click Download to save a PDF with 4 puzzles and an optional answer key page.

Grid	Digits used	Cells	Best for
6×6	1 – 6	36	Beginners, younger students (Grade 4+), quick practice
9×9	1 – 9	81	Regular solvers, Grades 6+, enrichment and logic clubs

The 6×6 grid has fewer possible digit combinations per cage, so arithmetic checks resolve faster. The 9×9 demands more sustained reasoning — pairs of cages interact across the larger grid, and division cages become harder to resolve when the digit pool goes up to 9. Both grids share identical rules; only the number range and grid dimensions differ.

If calcudoku feels comfortable and you want a variant with a different twist, try classic Sudoku (no arithmetic) or Sum Sudoku (border sum clues instead of cage operations).

1. Resolve single-cell cages first

A cage containing only one cell shows the cell's value directly — write it in immediately. These free cells then constrain the remaining cells in the same row and column.

2. List possible digit sets for each cage

For a 2-cell cage labelled 12× in a 9×9 grid, the pairs that multiply to 12 are: {3,4}, {2,6}, {1,12} — but 12 is out of range, so only {3,4} and {2,6} are valid. Write these pairs in pencil above the cage. As rows and columns fill in, you can eliminate options until only one remains.

3. Use row and column constraints to break ties

Once you know a cage is either {3,4} or {2,6}, check which digits are already placed in the same row or column as the cage cells. If 3 is already in that row, the {3,4} option is eliminated and {2,6} must be correct.

4. Watch for forced placements inside a cage

Even when the digit set is certain, the order within the cage may still be open. Check each cell's row and column individually: if 3 can only go in one of the two cage cells (because the other cell's column already contains a 3), place it there.

• Start with the most constrained cages — the fewest valid digit combinations resolve fastest.
• Division cages narrow down quickly: in a 6×6 grid, a ÷2 cage in row 1 has very few valid pairs when only digits 1–6 are available.
• Subtraction cages with large targets (e.g., 5− in a 6×6) force the highest and lowest available digits into the cage.