| 1 | ÷ | 10 | × | ( | X | − | 100 | ) | − | ( | X | − | 200 | − | ( | 100 | + | ( | X | − | 100 | ) | × | 1 | ÷ | 10 | ) | ) | × | 1 | ÷ | 10 | = | 100 |
| Left side of the equation = | 1 10 | ( | X | − | 100 | ) | − | ( | X | − | 200 | − | ( | 100 | + | ( | X | − | 100 | ) | × | 1 | ÷ | 10 | ) | ) | × | 1 10 |
1 10 | ( | X | − | 100 | ) | − | ( | X | − | 200 | − | ( | 100 | + | ( | X | − | 100 | ) | × | 1 | ÷ | 10 | ) | ) | × | 1 10 | = | 100 |
| Left side of the equation = | 1 10 | X | − | 1 10 | × | 100 | − | ( | X | − | 200 | − | ( | 100 | + | ( | X | − | 100 | ) | × | 1 | ÷ | 10 | ) | ) | × | 1 10 |
| = | 1 10 | X | − | 10 | − | ( | X | − | 200 | − | ( | 100 | + | ( | X | − | 100 | ) | × | 1 | ÷ | 10 | ) | ) | × | 1 10 |
| = | 1 10 | X | − | 10 | − | X | × | 1 10 | + | 200 | × | 1 10 | + | ( | 100 | + | ( | X | − | 100 | ) | × | 1 | ÷ | 10 | ) | × | 1 10 |
| = | 1 10 | X | − | 10 | − | X | × | 1 10 | + | 20 | + | ( | 100 | + | ( | X | − | 100 | ) | × | 1 | ÷ | 10 | ) | × | 1 10 |
| = | 0 | X | + | 10 | + | ( | 100 | + | ( | X | − | 100 | ) | × | 1 | ÷ | 10 | ) | × | 1 10 |
| = | 0 | X | + | 10 | + | 100 | × | 1 10 | + | ( | X | − | 100 | ) | × | 1 | ÷ | 10 | × | 1 10 |
| = | 0 | X | + | 10 | + | 10 | + | ( | X | − | 100 | ) | × | 1 100 |
| = | 0 | X | + | 20 | + | ( | X | − | 100 | ) | × | 1 100 |
| = | 0 | X | + | 20 | + | X | × | 1 100 | − | 100 | × | 1 100 |
| = | 0 | X | + | 20 | + | X | × | 1 100 | − | 1 |
| = | 1 100 | X | + | 19 |
1 100 | X | + | 19 | = | 100 |
1 100 | X | = | 100 | − | 19 |
1 100 | X | = | 81 |
| X | = | 81 | ÷ | 1 100 |
| = | 81 | × | 100 |
| X | = | 8100 |