| 16 | ( | 1000 | + | 1 8 | a | ) | + | ( | 20 | + | 1 20 | a | ) | ( | 1000 | − | 2 | a | ) | = | 36000 |
| Left side of the equation = | 16 | × | 1000 | + | 16 | × | 1 8 | a | + | ( | 20 | + | 1 20 | a | ) | ( | 1000 | − | 2 | a | ) |
| = | 16000 | + | 2 | a | + | ( | 20 | + | 1 20 | a | ) | ( | 1000 | − | 2 | a | ) |
| = | 16000 | + | 2 | a | + | 20 | ( | 1000 | − | 2 | a | ) | + | 1 20 | a | ( | 1000 | − | 2 | a | ) |
| = | 16000 | + | 2 | a | + | 20 | × | 1000 | − | 20 | × | 2 | a | + | 1 20 | a | ( | 1000 | − | 2 | a | ) |
| = | 16000 | + | 2 | a | + | 20000 | − | 40 | a | + | 1 20 | a | ( | 1000 | − | 2 | a | ) |
| = | 36000 | − | 38 | a | + | 1 20 | a | ( | 1000 | − | 2 | a | ) |
| = | 36000 | − | 38 | a | + | 1 20 | a | × | 1000 | − | 1 20 | a | × | 2 | a |
| = | 36000 | − | 38 | a | + | 50 | a | − | 1 10 | a | a |
| = | 36000 | + | 12 | a | − | 1 10 | a | a |
| 36000 | + | 12 | a | − | 1 10 | a | a | = | 36000 |