| 100 | ÷ | ( | 1 | + | 7 100 | + | a | ) | = | 1 |
| Multiply both sides of the equation by: | ( | 1 | + | 7 100 | + | a | ) |
| 100 | = | 1 | ( | 1 | + | 7 100 | + | a | ) |
| 100 | = | 1 | × | 1 | + | 1 | × | 7 100 | + | 1 | a |
| 100 | = | 1 | + | 7 100 | + | 1 | a |
| 100 | = | 107 100 | + | 1 | a |
| - | 1 | a | = | 107 100 | − | 100 |
| - | a | = | 107 100 | − | 100 |
| - | a | = | - | 9893 100 |
9893 100 | = | a |
| a | = | 9893 100 |