| 100 | × | 30 100 | = | ( | 100 | + | m | ) | × | 3 100 |
| Left side of the equation = | 30 |
| 30 | = | ( | 100 | + | m | ) | × | 3 100 |
| Right side of the equation = | 100 | × | 3 100 | + | m | × | 3 100 |
| = | 3 | + | m | × | 3 100 |
| 30 | = | 3 | + | 3 100 | m |
| - | 3 100 | m | = | 3 | − | 30 |
| - | 3 100 | m | = | - | 27 |
| 27 | = | 3 100 | m |
3 100 | m | = | 27 |
| m | = | 27 | ÷ | 3 100 |
| = | 27 | × | 100 3 |
| = | 9 | × | 100 |
| m | = | 900 |