| 405 | X | × | 127 50 | ( | 28 | − | 253 | ÷ | 10 | ) | = | 0 |
| 方程左边 = | 10287 10 | X | ( | 28 | − | 253 | ÷ | 10 | ) |
10287 10 | X | ( | 28 | − | 253 | ÷ | 10 | ) | = | 0 |
| 方程左边 = | 10287 10 | X | × | 28 | − | 10287 10 | X | × | 253 | ÷ | 10 |
| = | 144018 5 | X | − | 2602611 100 | X |
| = | 277749 100 | X |
277749 100 | X | = | 0 |
| X | = | 0 | ÷ | 277749 100 |
| = | 0 | × | 100 277749 |
| X | = | 0 |