Guide • Calcudoku

How to Play Calcudoku

Calcudoku, also known as KenKen, is a sudoku-like game but with math. The goal is to fill in the grid with numbers so that rows and columns have no repeats while also satisfying the puzzle math.

Rules

The board is divided into cells and cages.
Each cell gets a numeric value 1, 2, 3... (for a 4×4, numbers 1–4)
Numbers cannot repeat in any row or column.
A cage is a collection of adjacent cells that function as a group.
Each cage has an operation in the format result:operation, such as 3* or 9+.
The values of the cells in a cage must match the operation. For example, the 3* cage must be 3*1 or 1*3.
Single-cell cages are called reveals and already show the correct value.

Calcudoku grid with cages and targets highlighted

Basic strategy

Look for cages with the fewest possible combinations. For example, 8* can only be 4 * 2 * 1 (in any order).
Remember that each row and column must have each of the values exactly once. Since 4,2,1 is used by the 8* cage we know the first cell of the 9+ cage must be a 3.
Similarly the last cage can only be 4 ÷ 2 or 2 ÷ 1. In either case a 2 is required so we know that the 2 for the other 2÷ cage must go in row 3.

More strategies

Look for the highest or lowest value operations because they usually have fewer options. For example 9+ can only be 4 + 3 + 2 since all the cells are in a single column. That means the last cell must be a 1.
That allows us to easily solve both 2÷ cages since one must be 2 ÷ 1 and the other 4 ÷ 2.
After each move scan the puzzle to see if there are any force values. For example now that we a 2 in columns 2 and 3 we know that the the first cell of the 8* cage must be a 2.

General Tips

Use the notes feature to record candidate values in cells.
Consider taking a hint if you get stuck.
Prefer multiplication/addition cages early; they limit candidates quickly.
Re-scan after each placement—Calcudoku cascades fast.