| - | 40 | − | x | − | x | × | 4 100 | ÷ | 4 | − | 20 | = | 50 |
| Left side of the equation = | - | 40 | − | x | − | x | × | 1 100 | − | 20 |
| = | - | 60 | − | 101 100 | x |
| - | 60 | − | 101 100 | x | = | 50 |
| - | 101 100 | x | = | 50 | + | 60 |
| - | 101 100 | x | = | 110 |
| - | 110 | = | 101 100 | x |
101 100 | x | = | - | 110 |
| x | = | - | 110 | ÷ | 101 100 |
| = | - | 110 | × | 100 101 |
| x | = | - | 11000 101 |
| x | = | - 108.910891 |