| 5 | ÷ | 12 | × | ( | X | − | 4 | ) | + | 4 | = | 6 | ÷ | 13 | × | X |
| 方程左边 = | 5 12 | ( | X | − | 4 | ) | + | 4 |
5 12 | ( | X | − | 4 | ) | + | 4 | = | 6 | ÷ | 13 | × | X |
| 方程左边 = | 5 12 | X | − | 5 12 | × | 4 | + | 4 |
| = | 5 12 | X | − | 5 3 | + | 4 |
| = | 5 12 | X | + | 7 3 |
5 12 | X | + | 7 3 | = | 6 | ÷ | 13 | × | X |
| 方程右边 = | 6 13 | X |
5 12 | X | + | 7 3 | = | 6 13 | X |
5 12 | X | − | 6 13 | X | = | - | 7 3 |
| - | 7 156 | X | = | - | 7 3 |
7 3 | = | 7 156 | X |
7 156 | X | = | 7 3 |
| X | = | 7 3 | ÷ | 7 156 |
| = | 7 3 | × | 156 7 |
| = | 1 | × | 52 |
| X | = | 52 |