| 12 | ÷ | 103 | + | 20 | ÷ | 200 | + | X | ÷ | 1000 | + | ( | 131 2 | − | X | ) | ÷ | 1650 | = | 3 10 |
| 方程左边 = | 12 103 | + | 1 10 | + | X | × | 1 1000 | + | ( | 131 2 | − | X | ) | × | 1 1650 |
| = | 223 1030 | + | 1 1000 | X | + | ( | 131 2 | − | X | ) | × | 1 1650 |
223 1030 | + | 1 1000 | X | + | ( | 131 2 | − | X | ) | × | 1 1650 | = | 3 10 |
| 方程左边 = | 223 1030 | + | 1 1000 | X | + | 131 2 | × | 1 1650 | − | X | × | 1 1650 |
| = | 223 1030 | + | 1 1000 | X | + | 131 3300 | − | X | × | 1 1650 |
| = | 87083 339900 | + | 13 33000 | X |
87083 339900 | + | 13 33000 | X | = | 3 10 |
13 33000 | X | = | 3 10 | − | 87083 339900 |
13 33000 | X | = | 14887 339900 |
| X | = | 14887 339900 | ÷ | 13 33000 |
| = | 14887 339900 | × | 33000 13 |
| = | 14887 1133 | × | 110 13 |
| X | = | 1637570 14729 |
| X | = | 148870 1339 |
| X | = | 111.179985 |