Puzzle · Logic Puzzle
Calcudoku
Play Calcudoku online. Fill a Latin square with numbers that satisfy each arithmetic cage. Rows and columns cannot repeat a digit.
The game's own interface may still be in English.
Overview
Calcudoku combines a Latin square with arithmetic cages. On a board of a given size, every row and column must contain each number from one to that size exactly once. Thick cage borders add a second set of constraints: the numbers inside each cage must produce its target using the displayed operation. There are no Sudoku boxes unless the cage arrangement happens to resemble them. Addition cages reward combination counting, while multiplication cages introduce factor reasoning. Subtraction and division require special attention to the relationship between the cage values. SonoTap hosts the open-source Keen implementation locally, with generated puzzles and selectable sizes. You can take notes, undo a chain of entries, or change to a smaller board while learning the rules.
How to Play
Click or tap an empty square, then type a digit or choose an on-screen number. Use arrow keys or arrow buttons to move the selected cell. Backspace clears an entry. To add candidate pencil marks, use a secondary click to select the square before entering the candidate numbers; on a phone, turn on Secondary for that selection. Complete both the row-and-column restrictions and the arithmetic cages. Restart returns to the original clues, while New creates another board with the selected Type settings.
Tips & Strategy
Resolve one-cell cages first, then list the possible combinations for small cages with unusually high or low targets. A two-cell multiplication cage targeting a prime number has very few options within a small board's digit range. Cross-check every arithmetic possibility against digits already used in its row and column. Do not assume that two cells in the same cage may repeat a number: even when the arithmetic allows it, a shared row or column forbids it. Keep pencil marks selective, removing a candidate when another cage fixes the same number on that line.
About this version
Calcudoku uses the locally compiled keen engine from Simon Tatham’s Portable Puzzle Collection. The original authors retain credit under the MIT license. SonoTap provides the browser adaptation and this guide.
Controls
- Keyboard
- 1–9 — enter a value in the selected cellArrow keys — move the selectionBackspace — erase an entry
- Mouse
- Click or tap an empty square, then type a digit or choose an on-screen number. Use arrow keys or arrow buttons to move the selected cell. Backspace clears an entry. To add candidate pencil marks, use a secondary click to select the square before entering the candidate numbers; on a phone, turn on Secondary for that selection. Complete both the row-and-column restrictions and the arithmetic cages. Restart returns to the original clues, while New creates another board with the selected Type settings.
- Touch
- Tap or drag on the board using the same rules as mouse input. Enable Secondary for the alternate mark; numeric games also provide on-screen keys.
Features
- Fill a Latin square with numbers that satisfy each arithmetic cage. Rows and columns cannot repeat a digit.
- Local open-source game engine with original author credits
- Generated puzzles and the upstream Type settings
- Undo and restart controls
- Touch input and a secondary-action toggle
Frequently asked questions
What is the goal in Calcudoku?
Fill a Latin square with numbers that satisfy each arithmetic cage. Rows and columns cannot repeat a digit.
What is a useful first deduction in Calcudoku?
Resolve one-cell cages first, then list the possible combinations for small cages with unusually high or low targets. A two-cell multiplication cage targeting a prime number has very few options within a small board's digit range.