How to Play Calcudoku

Overview

Calcudoku (also known as KenKen or Mathdoku) combines the logic of Sudoku with arithmetic. Fill the grid so each row and column contains each digit exactly once, while satisfying the mathematical constraints in each cage.

Video Tutorial

Rules

  • 1Fill each cell with a digit from 1 to N (where N is the grid size).
  • 2Each row must contain each digit exactly once.
  • 3Each column must contain each digit exactly once.
  • 4Cells are grouped into cages with a target number and operation.
  • 5Digits in each cage must combine using the operation to equal the target.

Operations

+
Addition: 7+ with [3,4] → 3+4=7
Subtraction: 2− with [5,3] → 5−3=2
×
Multiplication: 12× with [3,4] → 3×4=12
÷
Division: 2÷ with [6,3] → 6÷3=2

Controls

ClickSelect a cell
1-9 KeysEnter a digit
BackspaceClear selected cell
P KeyToggle pencil mode
Ctrl+ZUndo last move

Solving Strategies

Single-Cell Cages

A cage with one cell gives you a free digit!

Division is Restrictive

Division cages have limited options (e.g., 2÷ must be 2/1, 4/2, or 6/3).

Use Pencil Marks

Note possible candidates to track possibilities and eliminate options.

Cross-Reference

Check rows and columns together to find where a digit must go.