How to Play Calcudoku
Calcudoku is sudoku's arithmetic cousin: no digits are given, and the clues are little sums.
The rules
- Fill the grid with the digits 1 to N (N is the size of the grid), so that each digit appears once in every row and once in every column.
- Thick lines divide the grid into cages. The number in a cage's corner is its target, and the sign is the operation: the digits in the cage must add, multiply, subtract or divide to the target.
- A cage with − or ÷ always has two cells, and the order doesn't matter.
- A cage with a number and no sign is a single cell: that's its digit.
- Digits may repeat inside a cage as long as they're in different rows and columns.
Every puzzle on kawu has exactly one solution.
Playing on kawu
- Pick a cell and type a digit, or use the digit pad. Shift + digit (or the Notes toggle) writes a small candidate.
- Repeats and finished cages that don't make their target are marked.
- Hint fills one cell, choosing the one with the fewest possibilities.
- 4×4, 5×5 and 6×6 sizes; the daily puzzle is the same for everyone.
Next, read the Calcudoku techniques. Like it? Try Futoshiki or Killer Sudoku.
Frequently asked questions
Can a digit repeat inside a cage?
Yes, if the two cells are in different rows and different columns. An L-shaped cage can hold the same digit twice; a straight cage can't.
Does the order matter in a − or ÷ cage?
No. The cage shows the difference or the quotient; the bigger digit can be in either cell.
Is Calcudoku the same as KenKen?
The rules are the same family of puzzle. KenKen is a trademark; Calcudoku is the generic name.
Last updated 2026-10-20