Understand Kakuro combinations
A cross-sum puzzle combines arithmetic with a no-repeat rule inside each run. Checking a sum alone can miss a repeated digit.
By Zehano · Original AI-assisted explanation and worked example · Updated 16 October 2026 · Editorial approach
A worked example
A two-cell run totalling four can use 1 and 3 in either order. It cannot use 2 and 2 because the run repeats a digit. Intersecting column sums can determine the order. In the grid with rows 1,3 and 4,2, the row sums are 4 and 6 while the column sums are 5 and 5. Check all four runs rather than stopping after one correct row.
Try it in three steps
- List distinct-digit combinations for a run.
- Use crossing clues to narrow the positions.
- Verify every row and column.
What to watch for
The compact Zehano board accepts any complete solution satisfying its sums and no-repeat rules. A hint follows one example solution, which need not be the only valid one.
Apply it to your own material
Choose one topic from your current course or project. Write down the question you want to answer, make an attempt, and keep a note of how you checked it. Use the example above as a pattern; replace its subject matter and assumptions rather than copying an answer into a different task.
Open Kakuro ↗