Calcudoku
Sudoku meets arithmetic in this challenging math puzzle.
The rules
How to play
- 01
Fill the grid
Enter a digit from 1 to N in every cell, where N is the grid size — a 6×6 grid uses the digits 1 through 6.
- 02
Rows
Each row must contain every digit exactly once. No digit ever repeats across a row.
- 03
Columns
The same rule applies vertically: each column holds every digit exactly once, top to bottom.
- 04
Cages
Bold outlines group cells into cages. Each cage shows a target number and an arithmetic operation in its corner.
- 05
Do the math
The digits inside a cage must combine with its operation to equal the target. A single-cell cage simply hands you that digit.
Play smarter
Six habits of fast solvers
Solve single-cell cages
A cage holding just one cell states its digit outright — place every one of these first.
Division is restrictive
Division cages have few options: a 2÷ cage must be 2/1, 4/2, or 6/3. Start where choices are scarce.
List the combinations
For an addition or multiplication cage, write out every digit pair that hits the target, then eliminate.
Use pencil marks
Note candidate digits in empty cells to track possibilities and cross off options as they fall.
Cross-reference lines
Read a row and column together — the intersection often forces a single digit into place.
Mind low targets
Small targets in large cages severely limit the digits that can fit, so they crack open quickly.
Watch & learn
Two minutes to mastery
From the Intel desk
Reading for the curious
Calcudoku Puzzle: A Complete Beginner's Guide to Math Cages
Learn how to solve Calcudoku puzzles from scratch. Master the rules, understand cage arithmetic, follow our visual step-by-step tutorial, and discover essential strategies for this addictive math-logic hybrid also known as KenKen.
Calcudoku Strategies: Cage Combinations Every Solver Must Know
Master Calcudoku and KenKen with cage combination analysis, operation logic, and cross-cage techniques. Essential kenken strategies and calcudoku tips from beginner to expert.
Keep going
Where to next
Fresh every day
The Daily Calcudoku
One shared math grid for everyone, every day. Build a streak and compare your time.
Go deeper
Rules & strategy guide
Every operation, cage type, and solving tactic laid out in the complete written guide.
Beyond the grid
Explore all puzzles
Sudoku, Kakuro, Nonograms and fifteen more logic games await.