Calcudoku

About Calcudoku

Calcudoku is a math logic puzzle that mixes Sudoku-style rules with arithmetic, free to play in your browser. Fill a square grid with the numbers 1 to N so that no number repeats in any row or column. The grid is divided into outlined cages, and each cage shows a target and an operation: the numbers inside must add, subtract, multiply or divide to make that target. Subtraction and division cages always cover two squares. Start with a gentle 4x4, settle into 6x6 at normal or harder levels, or tackle a full 9x9, with multiplication-only variants for extra variety. Tap a square and choose a number from the on-screen pad, keep pencil notes for candidates, and undo whenever you like. Each puzzle has one unique answer, and your progress is saved.

Game by Simon Tatham, used under the MIT license.

How to play

Tap a square, then tap a number on the pad (⌫ clears). Pencil mode or a long-press adds candidate notes. Keyboard: arrows move, digits enter, Enter toggles pencil, M fills all candidates.