| x | ÷ | 20 | = | ( | 100 | × | 100 | ÷ | ( | 100 | + | 100 | ) | ) |
| x | ÷ | 20 | = | 100 | × | 100 | ÷ | ( | 100 | + | 100 | ) |
| x | × | 1 20 | = | 10000 | ÷ | ( | 100 | + | 100 | ) |
| 方程两边同时乘以: | ( | 100 | + | 100 | ) |
1 20 | x | ( | 100 | + | 100 | ) | = | 10000 |
1 20 | x | × | 100 | + | 1 20 | x | × | 100 | = | 10000 |
| 5 | x | + | 5 | x | = | 10000 |
| 10 | x | = | 10000 |
| x | = | 10000 | ÷ | 10 |
| = | 10000 | × | 1 10 |
| = | 1000 | × | 1 |
| x | = | 1000 |