| ( | m | − | 13 | ) | ÷ | 2 | = | m | − | ( | 12 | × | 2 | ) | ÷ | 3 | + | 12 |
| Left side of the equation = | m | × | 1 2 | − | 13 | × | 1 2 |
| = | m | × | 1 2 | − | 13 2 |
1 2 | m | − | 13 2 | = | m | − | ( | 12 | × | 2 | ) | ÷ | 3 | + | 12 |
| Right side of the equation = | m | − | 12 | × | 2 | × | 1 3 | + | 12 |
| = | m | − | 8 | + | 12 |
| = | m | + | 4 |
1 2 | m | − | 13 2 | = | m | + | 4 |
1 2 | m | − | m | = | 4 | + | 13 2 |
| - | 1 2 | m | = | 4 | + | 13 2 |
| - | 1 2 | m | = | 21 2 |
| - | 21 2 | = | 1 2 | m |
1 2 | m | = | - | 21 2 |
| m | = | - | 21 2 | ÷ | 1 2 |
| = | - | 21 2 | × | 2 |
| = | - | 21 | × | 1 |
| m | = | - | 21 |