Calcudoku
Free online number puzzle · New puzzle every day · No sign-up
Calcudoku in a nutshell
Calcudoku is a number puzzle that mixes Sudoku with simple sums. Fill the grid so each row and column has every number once, and make the numbers in each outlined cage reach the target using the sign shown. The sums are easy; the fun is in the logic.
- Know the numbers. A 4 by 4 grid uses 1 to 4, a 6 by 6 grid uses 1 to 6, and so on.
- No repeats in a line. Each number appears exactly once in every row and every column.
- Read the cages. Thick lines mark groups of squares called cages. Each cage shows a target number and a sign.
- Hit the target. The numbers in a cage must make the target using the sign: add, take away, multiply or divide.
At a glance
- Players
- 1 player at your own pace
- Length
- 5 to 30 minutes depending on size
- Equipment
- Square grid from 3 by 3 to 9 by 9
- Learn it in
- 5 minutes simple adding and multiplying
Calcudoku questions
Is Calcudoku the same as Mathdoku?
Yes. The same puzzle is called Calcudoku, Mathdoku, maths Sudoku and several other names.
Can a number repeat inside a cage?
Yes, as long as the repeated numbers are not in the same row or column. This often happens in L-shaped cages.
How do take-away and divide cages work?
They always have two squares. Take the smaller number from the larger, or divide the larger by the smaller. The order of the squares does not matter.
Do I need to be good at maths?
Only simple sums are needed, and small grids use small numbers. Most of the puzzle is logic, like Sudoku.
Is there a box rule, like in Sudoku?
No. Unlike Sudoku, Calcudoku has no 3 by 3 boxes. Only rows, columns and cages matter.
