| ( | 240 | − | X | ) | × | 3 | ÷ | 5 | − | 1 | ÷ | 3 | × | X | = | 4 |
| Left side of the equation = | ( | 240 | − | X | ) | × | 3 5 | − | 1 3 | X |
| ( | 240 | − | X | ) | × | 3 5 | − | 1 3 | X | = | 4 |
| Left side of the equation = | 240 | × | 3 5 | − | X | × | 3 5 | − | 1 3 | X |
| = | 144 | − | X | × | 3 5 | − | 1 3 | X |
| = | 144 | − | 14 15 | X |
| 144 | − | 14 15 | X | = | 4 |
| - | 14 15 | X | = | 4 | − | 144 |
| - | 14 15 | X | = | - | 140 |
| 140 | = | 14 15 | X |
14 15 | X | = | 140 |
| X | = | 140 | ÷ | 14 15 |
| = | 140 | × | 15 14 |
| = | 10 | × | 15 |
| X | = | 150 |