| ( | 500 | − | x | ) | × | 1000 | − | 50000 | = | 242000 |
| 方程左边 = | 500 | × | 1000 | − | x | × | 1000 | − | 50000 |
| = | 500000 | − | x | × | 1000 | − | 50000 |
| = | 450000 | − | 1000 | x |
| 450000 | − | 1000 | x | = | 242000 |
| - | 1000 | x | = | 242000 | − | 450000 |
| - | 1000 | x | = | - | 208000 |
| 208000 | = | 1000 | x |
| 1000 | x | = | 208000 |
| x | = | 208000 | ÷ | 1000 |
| = | 208000 | × | 1 1000 |
| = | 208 | × | 1 |
| x | = | 208 |