How to Play Calcudoku

THE PLAYBOOK · SSNHJ

How to play Calcudoku

Calcudoku gives you a focused activity to play in your browser. Fill a 4×4 Latin square and satisfy every cage arithmetic target. Check the relevant rule before repeating a move. Treat the first round as a chance to learn the controls. Choose a clear next step rather than rushing through the instructions.

Twelve puzzles with addition, multiplication, subtraction and singleton cages.

Focus on one rule

Choose one rule to keep in mind for this round. Apply it consistently rather than guessing what another version might allow. Refer to the controls when needed.

Your goal

Fill a 4×4 Latin square and satisfy every cage arithmetic target. An attractive position is not enough unless the goal is met. Return to the instructions when a step is unclear.

Step by step

1. Select a square and enter 1–4.
2. Combine all cage digits using its shown operation.
3. Subtraction uses the absolute difference.
4. Check puzzle verifies the entire grid.

Controls

Click or tap squares or graph edges. Number boards include a digit pad. Undo reverses the previous change; Check puzzle validates the solution. On a smaller screen, keep the active part of the board within view. A new-round button replaces the current round.

A useful example

A two-cell 6× cage contains 2 and 3 in a 1–4 puzzle. Apply the same reasoning to the position in your own round. Consider the next action carefully.

Watch out for this

A correct cage total does not permit duplicate digits in a row. Check the rule before repeating the action. When a decision goes wrong, compare it with the common mistake described below. Start again only when you intend to leave the current round.

Common questions