| ( | 1 10 | y | + | 57 1000 | ) | ÷ | 21 100 | = | 0 |
| Left side of the equation = | 1 10 | y | × | 100 21 | + | 57 1000 | × | 100 21 |
| = | 10 21 | y | + | 19 70 |
10 21 | y | + | 19 70 | = | 0 |
10 21 | y | = | 0 | − | 19 70 |
10 21 | y | = | - | 19 70 |
| y | = | - | 19 70 | ÷ | 10 21 |
| = | - | 19 70 | × | 21 10 |
| = | - | 19 10 | × | 3 10 |
| y | = | - | 57 100 |
| y | = | - 0.57 |