| ( | 50 | − | 28 | − | m | ) | ( | 100 | + | 4 | m | ) | = | 2088 |
| 方程左边 = | 50 | ( | 100 | + | 4 | m | ) | − | 28 | ( | 100 | + | 4 | m | ) | − | m | ( | 100 | + | 4 | m | ) |
| = | 50 | × | 100 | + | 50 | × | 4 | m | − | 28 | ( | 100 | + | 4 | m | ) | − | m | ( | 100 | + | 4 | m | ) |
| = | 5000 | + | 200 | m | − | 28 | ( | 100 | + | 4 | m | ) | − | m | ( | 100 | + | 4 | m | ) |
| = | 5000 | + | 200 | m | − | 28 | × | 100 | − | 28 | × | 4 | m | − | m | ( | 100 | + | 4 | m | ) |
| = | 5000 | + | 200 | m | − | 2800 | − | 112 | m | − | m | ( | 100 | + | 4 | m | ) |
| = | 2200 | + | 88 | m | − | m | ( | 100 | + | 4 | m | ) |
| = | 2200 | + | 88 | m | − | m | × | 100 | − | m | × | 4 | m |
| = | 2200 | − | 12 | m | − | m | × | 4 | m |
| 2200 | − | 12 | m | − | m | × | 4 | m | = | 2088 |