| 2251 | ÷ | 77500 | = | 124200 | × | 81 50 | ÷ | 310000 | − | 1 1000 | x |
| 方程左边 = | 2251 77500 |
2251 77500 | = | 124200 | × | 81 50 | ÷ | 310000 | − | 1 1000 | x |
| 方程右边 = | 50301 77500 | − | 1 1000 | x |
2251 77500 | = | 50301 77500 | − | 1 1000 | x |
1 1000 | x | = | 50301 77500 | − | 2251 77500 |
1 1000 | x | = | 31 50 |
| x | = | 31 50 | ÷ | 1 1000 |
| = | 31 50 | × | 1000 |
| = | 31 | × | 20 |
| x | = | 620 |