Calcudoku is a number puzzle like Sudoku, with arithmetic added. Fill the grid so every row and column has each digit once, and every cage inside the thick lines makes its target number. It is the same kind of puzzle as KenKen. Every puzzle here has exactly one solution and can be solved by logic, with no guessing.
Write one digit in every square. In a 4 × 4 grid the digits are 1 to 4, in a 6 × 6 grid 1 to 6, and so on. Each digit appears once in every row and once in every column.
Thick lines split the grid into cages. The small number and sign in a cage’s corner is its target: the digits in the cage must make that number with that operation. For 6+ the digits add up to 6; for 12× they multiply to 12. In a 1− cage the two digits differ by 1, and in a 2÷ cage one digit is twice the other. A cage with just a number is a single square, and that number is its digit.
A digit can repeat inside a cage, as long as its squares are in different rows and columns.
Choose how many operations to use. Addition only is the gentlest start for children who are learning sums. Addition and subtraction adds cages where two digits differ by a number. With all four operations, cages can also multiply and divide.
The level is how much reasoning a puzzle needs. Every puzzle can be solved by logic alone, with no guessing. Easy needs only the cages’ own arithmetic and simple elimination. Medium also combines a cage’s options with what the rows and columns rule out. Hard needs pairs, digits a cage must contain, or row and column totals, and gives no digits away on 5 × 5 and larger grids. Not every choice has all three levels: 3 × 3 has no Hard (and no Medium with addition only), and from 7 × 7 up, Hard needs all four operations.
Start with what is certain, then let the rows and columns do the work.
The printer button above the grid prints the puzzle you are playing, with a QR code that opens it online, and can add a page with the answer. To print many puzzles at once, use the worksheet maker on the printable page: pick the size, level and operations, and add an answer key on the last page.
A 4 × 4 grid with addition only works well as a first printable Calcudoku for kids, and 6 × 6 is a good next step.
Yes. Each puzzle is checked by a solver that finds every possible solution, and only puzzles with exactly one are used.
Yes, if the squares are in different rows and columns. In the same row or column a digit never repeats.
They are the same kind of puzzle. KenKen is a registered trademark of KenKen Puzzle LLC and is not affiliated with this site; the puzzles here are generated by this site.
Try 4 × 4, Easy, with addition only. Move up to 5 × 5 and 6 × 6, then add subtraction, multiplication and division.
Yes. Print one puzzle with an answer page from the printer button, or make a worksheet with an answer key on the printable page. It is free and needs no sign-up.
Calcudoku