| 1247000 | x | × | 1 10 | + | ( | 200 | − | x | ) | × | 1238000 | × | 1 10 | = | 42587200 |
| 方程左边 = | 124700 | x | + | ( | 200 | − | x | ) | × | 123800 |
| 124700 | x | + | ( | 200 | − | x | ) | × | 123800 | = | 42587200 |
| 方程左边 = | 124700 | x | + | 200 | × | 123800 | − | x | × | 123800 |
| = | 124700 | x | + | 24760000 | − | x | × | 123800 |
| = | 900 | x | + | 24760000 |
| 900 | x | + | 24760000 | = | 42587200 |
| 900 | x | = | 42587200 | − | 24760000 |
| 900 | x | = | 17827200 |
| x | = | 17827200 | ÷ | 900 |
| = | 17827200 | × | 1 900 |
| = | 19808 | × | 1 |
| x | = | 19808 |