Calcudoku

Calcudoku is a math logic puzzle: fill an N×N grid with digits 1 through N so no number repeats in any row or column, just like Sudoku. The twist is the bold-outlined "cages" carved into the grid — each one shows a target number and an operator (+, −, ×, ÷), and the digits inside it must combine to hit that target using every cell in the cage. A single-cell cage is a free space: its target is simply the answer. No pencil marks, no timers ticking against you — just row/column logic plus arithmetic, playable free in the browser with no download or sign-up.

How to play Calcudoku

1. Pick a level, then look at the grid: it's divided into bold-outlined "cages", each labeled in its top-left cell with a target number and an operator (+, −, ×, ÷).
2. Tap a cell to select it, then tap a digit from the number pad (or press a number key) to fill it in.
3. Fill the whole grid so every row and every column contains each digit from 1 to the grid size exactly once, and every cage's digits combine via its operator to reach its target.
4. A single-cell cage shows only a number — no operator — because that digit is the only possible answer for that cell.
5. The puzzle is solved the moment every row, column, and cage checks out; mistakes and time are tracked so you can beat your own best run.

Tips

• Start with cages that only have one legal combination — on a 4×4 grid (digits 1-4), a 2-cell "7+" can only be 3+4, and a 2-cell "3×" can only be 1×3, so those cells are effectively solved before you touch anything else.
• Subtraction and division cages always have exactly 2 cells, so their target directly tells you the *difference* or *ratio* between two digits — list the few pairs that work, then use the row/column constraints to pick between them.
• Once a row or column has all but one digit placed, the last cell is forced — fill those in first before spending a hint on a cage you haven't fully thought through.

FAQ