Daily Calcudoku

How to play Calcudoku

Calcudoku (sometimes called KenKen) is an arithmetic grid puzzle. Fill every row and column with the digits 1 to N (where N is the grid size) — each digit appearing exactly once per row and column. The grid is divided into cages: each cage shows a target and an operator (+, −, ×, ÷). The digits inside the cage must combine using that operator to reach the target.

THE RULES

1. Every row must contain each digit 1–N exactly once.
2. Every column must contain each digit 1–N exactly once.
3. The digits in each cage must produce the cage's target using its operator (+, −, ×, ÷). Digits may repeat within a cage as long as rows and columns stay valid.
4. A cage marked = is a single pre-filled clue — its digit is given to you.

BEGINNER STRATEGY

• Start with forced cages. A single-cell cage gives you a free digit. A 2-cell addition cage near the maximum sum (e.g. "9+" in a 5×5) has very few valid pairs — enumerate them and eliminate with row/column logic.
• Use subtraction and division cages early. Order doesn't matter for + and ×, but − and ÷ lock the pair exactly (e.g. "2−" can only be {a, a+2} and "3÷" can only be {1, 3} or {2, 6}). These narrow candidates fast.
• Apply row/column exclusion. Once you know a cage must contain a particular digit, that digit can't appear elsewhere in the same row or column — use it to eliminate candidates in other cages.
• Digits can repeat in a cage (unlike Killer Sudoku). A 4-cell addition cage of "8+" in a 5×5 could include two 2s — as long as no row or column sees a duplicate.

ABOUT THIS DAILY

Every visitor on the same UTC day sees the same cage layout, seeded from the date. Your progress is saved to this browser — close the tab and come back later. A new puzzle unlocks at midnight UTC. If you enjoy the puzzle, GridJoy on Google Play has 17 more puzzle types (Sudoku, Killer Sudoku, Kakuro, and more) plus a ghost companion that grows with you as you solve.