| 300 | X | − | 2800000 | × | 120 | X | = | 1000000 |
| 方程左边 = | 300 | X | − | 336000000 | X |
| = | - | 335999700 | X |
| - | 335999700 | X | = | 1000000 |
| - | 1000000 | = | 335999700 | X |
| 335999700 | X | = | - | 1000000 |
| X | = | - | 1000000 | ÷ | 335999700 |
| = | - | 1000000 | × | 1 335999700 |
| = | - | 10000 | × | 1 3359997 |
| X | = | - | 10000 3359997 |
| X | = | - 0.002976 |