Kakuro: sum 20 in 4 cells
A sum of 20 in 4 cells can be made 12 ways.
| Combination | Digit set |
|---|---|
| 1 + 2 + 8 + 9 | 1289 |
| 1 + 3 + 7 + 9 | 1379 |
| 1 + 4 + 6 + 9 | 1469 |
| 1 + 4 + 7 + 8 | 1478 |
| 1 + 5 + 6 + 8 | 1568 |
| 2 + 3 + 6 + 9 | 2369 |
| 2 + 3 + 7 + 8 | 2378 |
| 2 + 4 + 5 + 9 | 2459 |
| 2 + 4 + 6 + 8 | 2468 |
| 2 + 5 + 6 + 7 | 2567 |
| 3 + 4 + 5 + 8 | 3458 |
| 3 + 4 + 6 + 7 | 3467 |
What this tells you
- There are 12 possibilities, so this clue alone does not decide the digits. Use crossing runs and any known cells to eliminate combinations.
- Every digit from 1 to 9 appears in at least one combination, so there is nothing to exclude outright.
Related sums
The digits left out of each combination form a combination for the mirror run: sum 25 in 5 cells (page).