How to Play Calcudoku

Basic Rules

1. Fill the Grid
Fill each cell with a digit from 1 to N, where N is the grid size. For a 6×6 grid, use digits 1-6.
2. Row Rule
Each row must contain each digit exactly once. No repeats allowed!
3. Column Rule
Each column must contain each digit exactly once.
4. Cage Constraints
Cells are grouped into "cages" marked by bold borders. Each cage shows a target number and a mathematical operation (+, −, ×, ÷).
5. Math Rules
The digits in each cage must combine using the operation to produce the target number. For subtraction and division, the larger number is always used first.

+Addition

7+ with cells [3, 4] → 3 + 4 = 7

−Subtraction

2− with cells [5, 3] → 5 − 3 = 2

×Multiplication

12× with cells [3, 4] → 3 × 4 = 12

÷Division

2÷ with cells [6, 3] → 6 ÷ 3 = 2

Start with single-cell cages — these give you free numbers!
Look for large targets in addition cages — they often have limited combinations.
Use pencil marks — write small candidate numbers to track possibilities.
Check rows and columns together — sometimes a cell is the only place a digit can go.
Division cages are restrictive — only certain digit pairs work (e.g., 2÷ must be pairs like 2,1 or 4,2).