23 100 | = | 105 100 | + | r | + | 105 100 | r |
| Right side of the equation = | 105 100 | + | 41 20 | r |
23 100 | = | 105 100 | + | 41 20 | r |
| - | 41 20 | r | = | 105 100 | − | 23 100 |
| - | 41 20 | r | = | 41 50 |
| - | 41 50 | = | 41 20 | r |
41 20 | r | = | - | 41 50 |
| r | = | - | 41 50 | ÷ | 41 20 |
| = | - | 41 50 | × | 20 41 |
| = | - | 1 5 | × | 2 |
| r | = | - | 2 5 |
| r | = | - 0.4 |