Kakuro Online Free
A crossword made of sums. Fill the white squares with the digits 1 to 9 so every across and down run adds up to its clue, without repeating a digit.
Tap a white square, then tap a number or type it. Arrow keys move between squares.
What is Kakuro?
Kakuro is a number puzzle, also called cross sums, that works like a crossword with numbers instead of letters. Each clue is a total, and the white squares in that run must add up to it using the digits 1 to 9, with no digit used twice in the same run.
It first appeared in American puzzle magazines as Cross Sums and became popular in Japan through the puzzle publisher Nikoli, which named it kasan kurosu (“addition cross”), shortened to Kakuro. Like Sudoku, it needs no guessing, but every step is also a small addition problem.
How to play Kakuro
- Black squares hold the clues. The number above the diagonal is the total for the white squares to its right. The number below the diagonal is the total for the white squares beneath it.
- Fill every white square with a digit from 1 to 9 so that each across run and each down run adds up to its clue.
- A digit can’t appear twice in the same run, but it can repeat elsewhere in the grid.
- Tap a white square, then tap a number or type it on your keyboard. Use ⌫ or Backspace to clear it, and the arrow keys to move.
- Repeated digits turn red, and so does a clue when its run goes over the total or is full but wrong. Every puzzle is made fresh and checked to have exactly one solution, so it can always be solved by logic without guessing. Use Hint if you’re stuck, and pick a size at the top of the board.
Kakuro skills
- Addition facts up to 45
- Finding sets of numbers with a given total
- Logical deduction
Level: Ages 9 and up
Tips for Kakuro
Learn the runs with only one answer. Two squares that make 3 must be 1 and 2, and two squares that make 17 must be 8 and 9. Three squares that make 6 are always 1, 2 and 3.
Where an across run and a down run cross, the square needs a digit that fits both. If the across run must be 1 and 2 and the down run must be 1 and 3, that square is 1.
Small totals use small digits and big totals use big digits. A 4-square run that makes 29 can only be 5, 7, 8 and 9. Practise the addition behind these in adding 3 numbers.
| 2 squares make 3 | 1, 2 |
|---|---|
| 2 squares make 4 | 1, 3 |
| 2 squares make 16 | 7, 9 |
| 2 squares make 17 | 8, 9 |
| 3 squares make 6 | 1, 2, 3 |
| 3 squares make 7 | 1, 2, 4 |
| 3 squares make 23 | 6, 8, 9 |
| 3 squares make 24 | 7, 8, 9 |
| 4 squares make 10 | 1, 2, 3, 4 |
| 4 squares make 11 | 1, 2, 3, 5 |
| 4 squares make 29 | 5, 7, 8, 9 |
| 4 squares make 30 | 6, 7, 8, 9 |
Kakuro questions and answers
How do you play Kakuro?
Fill each white square with a digit from 1 to 9. Every run of white squares across or down must add up to the clue at its start, and no digit may repeat within a run. The clue above a diagonal is for the run to the right; the clue below it is for the run going down.
Is Kakuro a math puzzle?
Yes. Every clue is an addition question in reverse: which different digits make 17 in two squares? Solving Kakuro practises addition facts and number combinations, along with the step-by-step logic of Sudoku.
What is the difference between Kakuro and Sudoku?
Both use the digits 1 to 9 without repeats, but Sudoku has no arithmetic: each row, column and box just needs every digit once. In Kakuro the runs are different lengths and each one must add up to a given total.
Does every Kakuro puzzle have one solution?
Yes. Every puzzle here is checked by a solver when it’s made, so there is exactly one way to fill the grid and you never need to guess.
Which Kakuro size should I start with?
Start with 6 × 6. The runs are short, so there are fewer combinations to think about. Move up to 8 × 8 and 10 × 10 when you know the common runs by heart.