| Subtraction | 8 | 9 | 10 | 11 | 12 |
| 16 | 8-16 = -8 | 9-16 = -7 | 10-16 = -6 | 11-16 = -5 | 12-16 = -4 |
| 17 | 8-17 = -9 | 9-17 = -8 | 10-17 = -7 | 11-17 = -6 | 12-17 = -5 |
| 18 | 8-18 = -10 | 9-18 = -9 | 10-18 = -8 | 11-18 = -7 | 12-18 = -6 |
| 19 | 8-19 = -11 | 9-19 = -10 | 10-19 = -9 | 11-19 = -8 | 12-19 = -7 |
| 20 | 8-20 = -12 | 9-20 = -11 | 10-20 = -10 | 11-20 = -9 | 12-20 = -8 |
| Subtraction | 7.1 | 7.2 | 7.3 | 7.4 | 7.5 | 7.6 |
| 15.1 | 7.1-15.1 = -8 | 7.2-15.1 = -7.9 | 7.3-15.1 = -7.8 | 7.4-15.1 = -7.7 | 7.5-15.1 = -7.6 | 7.6-15.1 = -7.5 |
| 15.2 | 7.1-15.2 = -8.1 | 7.2-15.2 = -8 | 7.3-15.2 = -7.9 | 7.4-15.2 = -7.8 | 7.5-15.2 = -7.7 | 7.6-15.2 = -7.6 |
| 15.3 | 7.1-15.3 = -8.2 | 7.2-15.3 = -8.1 | 7.3-15.3 = -8 | 7.4-15.3 = -7.9 | 7.5-15.3 = -7.8 | 7.6-15.3 = -7.7 |
| 15.4 | 7.1-15.4 = -8.3 | 7.2-15.4 = -8.2 | 7.3-15.4 = -8.1 | 7.4-15.4 = -8 | 7.5-15.4 = -7.9 | 7.6-15.4 = -7.8 |
| 15.5 | 7.1-15.5 = -8.4 | 7.2-15.5 = -8.3 | 7.3-15.5 = -8.2 | 7.4-15.5 = -8.1 | 7.5-15.5 = -8 | 7.6-15.5 = -7.9 |
| 15.6 | 7.1-15.6 = -8.5 | 7.2-15.6 = -8.4 | 7.3-15.6 = -8.3 | 7.4-15.6 = -8.2 | 7.5-15.6 = -8.1 | 7.6-15.6 = -8 |