| 5 | ÷ | 8 | × | 80 | × | 60 | = | ( | 80 | − | 4 | x | ) | ( | 60 | − | 2 | x | ) |
| 方程左边 = | 3000 |
| 3000 | = | ( | 80 | − | 4 | x | ) | ( | 60 | − | 2 | x | ) |
| 方程右边 = | 80 | ( | 60 | − | 2 | x | ) | − | 4 | x | ( | 60 | − | 2 | x | ) |
| = | 80 | × | 60 | − | 80 | × | 2 | x | − | 4 | x | ( | 60 | − | 2 | x | ) |
| = | 4800 | − | 160 | x | − | 4 | x | ( | 60 | − | 2 | x | ) |
| = | 4800 | − | 160 | x | − | 4 | x | × | 60 | + | 4 | x | × | 2 | x |
| = | 4800 | − | 160 | x | − | 240 | x | + | 8 | x | x |
| = | 4800 | − | 400 | x | + | 8 | x | x |
| 3000 | = | 4800 | − | 400 | x | + | 8 | x | x |