| ( | 168 | − | X | − | X | × | 10 100 | ) | ÷ | 4 | × | X | × | 3 | = | 30 |
| Left side of the equation = | ( | 168 | − | X | − | X | × | 10 100 | ) | × | 3 4 | X |
| ( | 168 | − | X | − | X | × | 10 100 | ) | × | 3 4 | X | = | 30 |
| Left side of the equation = | 168 | × | 3 4 | X | − | X | × | 3 4 | X | − | X | × | 10 100 | × | 3 4 | X |
| = | 126 | X | − | X | × | 3 4 | X | − | X | × | 3 40 | X |
| 126 | X | − | X | × | 3 4 | X | − | X | × | 3 40 | X | = | 30 |