| ( | 30 | ( | a | ÷ | 10 | ) | − | 15 | ) | × | 400 | + | 1000 | = | 4600 |
| Left side of the equation = | 30 | ( | a | ÷ | 10 | ) | × | 400 | − | 15 | × | 400 | + | 1000 |
| = | 12000 | ( | a | ÷ | 10 | ) | − | 6000 | + | 1000 |
| = | 12000 | ( | a | ÷ | 10 | ) | − | 5000 |
| = | 12000 | a | ÷ | 10 | − | 5000 |
| = | 1200 | a | − | 5000 |
| 1200 | a | − | 5000 | = | 4600 |
| 1200 | a | = | 4600 | + | 5000 |
| 1200 | a | = | 9600 |
| a | = | 9600 | ÷ | 1200 |
| = | 9600 | × | 1 1200 |
| = | 8 | × | 1 |
| a | = | 8 |