| Subtraction | 9 | 10 | 11 | 12 | 13 |
| 9 | 9-9 = 0 | 10-9 = 1 | 11-9 = 2 | 12-9 = 3 | 13-9 = 4 |
| 10 | 9-10 = -1 | 10-10 = 0 | 11-10 = 1 | 12-10 = 2 | 13-10 = 3 |
| 11 | 9-11 = -2 | 10-11 = -1 | 11-11 = 0 | 12-11 = 1 | 13-11 = 2 |
| 12 | 9-12 = -3 | 10-12 = -2 | 11-12 = -1 | 12-12 = 0 | 13-12 = 1 |
| 13 | 9-13 = -4 | 10-13 = -3 | 11-13 = -2 | 12-13 = -1 | 13-13 = 0 |