| 50 | × | 40 | × | 30 | + | ( | 40 | + | 2 | x | ) | ( | 50 | + | 3 | x | ) | × | 100 | = | 642000 |
| 方程左边 = | 60000 | + | ( | 40 | + | 2 | x | ) | ( | 50 | + | 3 | x | ) | × | 100 |
| 60000 | + | ( | 40 | + | 2 | x | ) | ( | 50 | + | 3 | x | ) | × | 100 | = | 642000 |
| 方程左边 = | 60000 | + | 40 | ( | 50 | + | 3 | x | ) | × | 100 | + | 2 | x | ( | 50 | + | 3 | x | ) | × | 100 |
| = | 60000 | + | 4000 | ( | 50 | + | 3 | x | ) | + | 200 | x | ( | 50 | + | 3 | x | ) |
| = | 60000 | + | 4000 | × | 50 | + | 4000 | × | 3 | x | + | 200 | x | ( | 50 | + | 3 | x | ) |
| = | 60000 | + | 200000 | + | 12000 | x | + | 200 | x | ( | 50 | + | 3 | x | ) |
| = | 260000 | + | 12000 | x | + | 200 | x | ( | 50 | + | 3 | x | ) |
| = | 260000 | + | 12000 | x | + | 200 | x | × | 50 | + | 200 | x | × | 3 | x |
| = | 260000 | + | 12000 | x | + | 10000 | x | + | 600 | x | x |
| = | 260000 | + | 22000 | x | + | 600 | x | x |
| 260000 | + | 22000 | x | + | 600 | x | x | = | 642000 |