Daily Calcudoku — Free Online Puzzle

How to play

Fill an N by N grid with the numbers 1 through N. Each row and each column must contain every number exactly once. There are no Sudoku boxes.

A cage is a connected group of cells bounded by a dashed outline. Its top-left label gives a target and an operation: + adds, - subtracts, x multiplies and ÷ divides. Subtraction and division cages have exactly two cells; use the larger number first. A cell with just a number is a fixed given.

Numbers can repeat inside a cage if they sit in different rows and columns. Tap a cell, then use the number pad or keyboard. Notes holds candidate numbers; Erase clears the selected cell and Undo restores an entry. Red marks show row or column repeats, or a completed cage with the wrong result.

Check compares entered digits with the unique solution. Show solution reveals the board and does not count as a daily solve. Solve the daily without revealing to add a consecutive UTC day to your streak. Your timer and entries are saved on this device.

A short history

Arithmetic cage puzzles were devised by Japanese mathematics teacher Tetsuya Miyamoto around 2004. They bring simple calculations into a grid where placement matters as much as the result. Read the puzzle history.

Code shuffles the rows, columns and symbols of a Latin square, grows connected cages, and checks their arithmetic together with the row and column rules. A puzzle is published only after an exact solution counter finds one solution. Try 4×4 to learn the rules, then move to a larger grid.

Solving tips

In a 6×6 grid, a two-cell 3- cage can hold 1 and 4, 2 and 5, or 3 and 6, in either order. Use the other numbers in each row and column to narrow the pair.

For a multiplication cage, list factor choices using only numbers up to the grid size. For division, the larger number divided by the smaller must equal the target exactly.

Keep candidate notes when several placements fit the arithmetic. A repeated number can be valid in a bent cage, but it cannot occur twice in one row or column. Start with single-cell givens and short cages.