| 100 | = | ( | 300 | − | 40 | ) | Q | − | ( | 280 | + | 120 | Q | ) |
| Right side of the equation = | 300 | Q | − | 40 | Q | − | ( | 280 | + | 120 | Q | ) |
| = | 260 | Q | − | ( | 280 | + | 120 | Q | ) |
| = | 260 | Q | − | 280 | − | 120 | Q |
| = | 140 | Q | − | 280 |
| 100 | = | 140 | Q | − | 280 |
| - | 140 | Q | = | - | 280 | − | 100 |
| - | 140 | Q | = | - | 380 |
| 380 | = | 140 | Q |
| 140 | Q | = | 380 |
| Q | = | 380 | ÷ | 140 |
| = | 380 | × | 1 140 |
| = | 19 | × | 1 7 |
| Q | = | 19 7 |
| Q | = | 2.714286 |