| 900000 | = | 50000 | ( | X | − | 10 | ) | − | 200000 |
| 方程右边 = | 50000 | X | − | 50000 | × | 10 | − | 200000 |
| = | 50000 | X | − | 500000 | − | 200000 |
| = | 50000 | X | − | 700000 |
| 900000 | = | 50000 | X | − | 700000 |
| - | 50000 | X | = | - | 700000 | − | 900000 |
| - | 50000 | X | = | - | 1600000 |
| 1600000 | = | 50000 | X |
| 50000 | X | = | 1600000 |
| X | = | 1600000 | ÷ | 50000 |
| = | 1600000 | × | 1 50000 |
| = | 32 | × | 1 |
| X | = | 32 |