| 7000 | × | 3000 | − | ( | ( | 7000 | − | 2 | x | ) | ( | 3000 | − | 2 | x | ) | ) | = | 8931648 |
| Left side of the equation = | 21000000 | − | ( | ( | 7000 | − | 2 | x | ) | ( | 3000 | − | 2 | x | ) | ) |
| 21000000 | − | ( | ( | 7000 | − | 2 | x | ) | ( | 3000 | − | 2 | x | ) | ) | = | 8931648 |
| Left side of the equation = | 21000000 | − | ( | 7000 | − | 2 | x | ) | ( | 3000 | − | 2 | x | ) |
| = | 21000000 | − | 7000 | ( | 3000 | − | 2 | x | ) | + | 2 | x | ( | 3000 | − | 2 | x | ) |
| = | 21000000 | − | 7000 | × | 3000 | + | 7000 | × | 2 | x | + | 2 | x | ( | 3000 | − | 2 | x | ) |
| = | 21000000 | − | 21000000 | + | 14000 | x | + | 2 | x | ( | 3000 | − | 2 | x | ) |
| = | 0 | + | 14000 | x | + | 2 | x | ( | 3000 | − | 2 | x | ) |
| = | 0 | + | 14000 | x | + | 2 | x | × | 3000 | − | 2 | x | × | 2 | x |
| = | 0 | + | 14000 | x | + | 6000 | x | − | 4 | x | x |
| = | 0 | + | 20000 | x | − | 4 | x | x |
| 0 | + | 20000 | x | − | 4 | x | x | = | 8931648 |