| ( | 1 | ÷ | ( | 100 | u | ) | ) | − | 1 20 | = | 1 | ÷ | ( | 20 | u | + | 20 | ) |
| Multiply both sides of the equation by: | ( | 20 | u | + | 20 | ) |
| ( | 1 | ÷ | ( | 100 | u | ) | ) | ( | 20 | u | + | 20 | ) | − | 1 20 | ( | 20 | u | + | 20 | ) | = | 1 |
| 1 | ÷ | ( | 100 | u | ) | × | ( | 20 | u | + | 20 | ) | − | 1 20 | ( | 20 | u | + | 20 | ) | = | 1 |
| Multiply both sides of the equation by: | ( | 100 | u | ) |
| 1 | ( | 20 | u | + | 20 | ) | − | 1 20 | ( | 20 | u | + | 20 | ) | ( | 100 | u | ) | = | 1 | ( | 100 | u | ) |
| 1 | × | 20 | u | + | 1 | × | 20 | − | 1 20 | ( | 20 | u | + | 20 | ) | ( | 100 | u | ) | = | 1 | ( | 100 | u | ) |
| 1 | × | 20 | u | + | 1 | × | 20 | − | 1 20 | ( | 20 | u | + | 20 | ) | ( | 100 | u | ) | = | 1 | × | 100 | u |
| 20 | u | + | 20 | − | 1 20 | ( | 20 | u | + | 20 | ) | ( | 100 | u | ) | = | 100 | u |
| 20 | u | + | 20 | − | 1 20 | × | 20 | u | ( | 100 | u | ) | − | 1 20 | × | 20 | ( | 100 | u | ) | = | 100 | u |
| 20 | u | + | 20 | − | 1 | u | ( | 100 | u | ) | − | 1 | ( | 100 | u | ) | = | 100 | u |
| 20 | u | + | 20 | − | 1 | u | × | 100 | u | − | 1 | ( | 100 | u | ) | = | 100 | u |
| 20 | u | + | 20 | − | 100 | u | u | − | 1 | ( | 100 | u | ) | = | 100 | u |
| 20 | u | + | 20 | − | 100 | u | u | − | 1 | × | 100 | u | = | 100 | u |
| 20 | u | + | 20 | − | 100 | u | u | − | 100 | u | = | 100 | u |
| - | 80 | u | + | 20 | − | 100 | u | u | = | 100 | u |