| ( | 16 | − | a | ) | ( | 160 | + | a | ÷ | 3 | × | 120 | ) | = | 3640 |
| 方程左边 = | 16 | ( | 160 | + | a | ÷ | 3 | × | 120 | ) | − | a | ( | 160 | + | a | ÷ | 3 | × | 120 | ) |
| = | 16 | × | 160 | + | 16 | a | ÷ | 3 | × | 120 | − | a | ( | 160 | + | a | ÷ | 3 | × | 120 | ) |
| = | 2560 | + | 640 | a | − | a | ( | 160 | + | a | ÷ | 3 | × | 120 | ) |
| = | 2560 | + | 640 | a | − | a | × | 160 | − | a | a | ÷ | 3 | × | 120 |
| = | 2560 | + | 640 | a | − | a | × | 160 | − | a | a | × | 40 |
| = | 2560 | + | 480 | a | − | a | a | × | 40 |
| 2560 | + | 480 | a | − | a | a | × | 40 | = | 3640 |