| ( | 2 | × | 5 | − | 1 | ) | × | 150 | = | ( | 4 | + | 6 | ) | A |
| Left side of the equation = | 2 | × | 5 | × | 150 | − | 1 | × | 150 |
| = | 1500 | − | 150 |
| = | 1350 |
| 1350 | = | ( | 4 | + | 6 | ) | A |
| Right side of the equation = | 4 | A | + | 6 | A |
| = | 10 | A |
| 1350 | = | 10 | A |
| - | 10 | A | = | - | 1350 |
| 1350 | = | 10 | A |
| 10 | A | = | 1350 |
| A | = | 1350 | ÷ | 10 |
| = | 1350 | × | 1 10 |
| = | 135 | × | 1 |
| A | = | 135 |