| ( | 4 | + | m | ) | × | 120 | × | 6 | + | 480 | = | 12 | × | 600 | + | 5760 |
| Left side of the equation = | ( | 4 | + | m | ) | × | 720 | + | 480 |
| ( | 4 | + | m | ) | × | 720 | + | 480 | = | 12 | × | 600 | + | 5760 |
| Left side of the equation = | 4 | × | 720 | + | m | × | 720 | + | 480 |
| = | 2880 | + | m | × | 720 | + | 480 |
| = | 3360 | + | 720 | m |
| 3360 | + | 720 | m | = | 12 | × | 600 | + | 5760 |
| Right side of the equation = | 7200 | + | 5760 |
| = | 12960 |
| 3360 | + | 720 | m | = | 12960 |
| 720 | m | = | 12960 | − | 3360 |
| 720 | m | = | 9600 |
| m | = | 9600 | ÷ | 720 |
| = | 9600 | × | 1 720 |
| = | 40 | × | 1 3 |
| m | = | 40 3 |
| m | = | 13.333333 |