| ( | 4 | ÷ | 15 | ) | ÷ | ( | 4 | ÷ | 25 | ) | = | ( | 4 | ÷ | 3 | ) | ÷ | ( | x | ÷ | x | ) |
| 方程两边同时乘以: | ( | 4 | ÷ | 25 | ) | , | ( | 1 | ÷ | 1 | ) |
| ( | 4 | ÷ | 15 | ) | ( | 1 | ÷ | 1 | ) | = | ( | 4 | ÷ | 3 | ) | ( | 4 | ÷ | 25 | ) |
| 4 | ÷ | 15 | × | ( | 1 | ÷ | 1 | ) | = | ( | 4 | ÷ | 3 | ) | ( | 4 | ÷ | 25 | ) |
| 4 | ÷ | 15 | × | ( | 1 | ÷ | 1 | ) | = | 4 | ÷ | 3 | × | ( | 4 | ÷ | 25 | ) |
4 15 | ( | 1 | ÷ | 1 | ) | = | 4 3 | ( | 4 | ÷ | 25 | ) |
4 15 | × | 1 | ÷ | 1 | = | 4 3 | ( | 4 | ÷ | 25 | ) |
4 15 | × | 1 | ÷ | 1 | = | 4 3 | × | 4 | ÷ | 25 |
4 15 | = | 16 75 |
| = | 16 75 | − | 4 15 |