Kakuro: sum 30 in 4 cells
A sum of 30 in 4 cells has exactly one digit set: 6+7+8+9.
| Combination | Digit set |
|---|---|
| 6 + 7 + 8 + 9 | 6789 |
What this tells you
- Unique. There is only one possibility, so as soon as you see this clue on a run of 4 cells you know the digits 6, 7, 8, 9 go in it. Only their order is open, and crossing runs usually decide that.
- Digits that can never appear: 1, 2, 3, 4, 5. You can remove them from every cell of the run.
Related sums
The digits left out of each combination form a combination for the mirror run: sum 15 in 5 cells (page).