| ( | 24 | − | m | − | 12 | ) | ( | 300 | + | 50 | m | ) | = | 4000 |
| Left side of the equation = | 24 | ( | 300 | + | 50 | m | ) | − | m | ( | 300 | + | 50 | m | ) | − | 12 | ( | 300 | + | 50 | m | ) |
| = | 24 | × | 300 | + | 24 | × | 50 | m | − | m | ( | 300 | + | 50 | m | ) | − | 12 | ( | 300 | + | 50 | m | ) |
| = | 7200 | + | 1200 | m | − | m | ( | 300 | + | 50 | m | ) | − | 12 | ( | 300 | + | 50 | m | ) |
| = | 7200 | + | 1200 | m | − | m | × | 300 | − | m | × | 50 | m | − | 12 | ( | 300 | + | 50 | m | ) |
| = | 7200 | + | 900 | m | − | m | × | 50 | m | − | 12 | ( | 300 | + | 50 | m | ) |
| = | 7200 | + | 900 | m | − | m | × | 50 | m | − | 12 | × | 300 | − | 12 | × | 50 | m |
| = | 7200 | + | 900 | m | − | m | × | 50 | m | − | 3600 | − | 600 | m |
| = | 3600 | + | 300 | m | − | m | × | 50 | m |
| 3600 | + | 300 | m | − | m | × | 50 | m | = | 4000 |