| s | ÷ | 5 | + | 9 | ÷ | 10 | + | s | ÷ | 4 | = | s | ÷ | 16 5 | + | s | ÷ | 4 |
| Left side of the equation = | s | × | 1 5 | + | 9 10 | + | s | × | 1 4 |
| = | 9 20 | s | + | 9 10 |
9 20 | s | + | 9 10 | = | s | ÷ | 16 5 | + | s | ÷ | 4 |
| Right side of the equation = | 9 16 | s |
9 20 | s | + | 9 10 | = | 9 16 | s |
9 20 | s | − | 9 16 | s | = | - | 9 10 |
| - | 9 80 | s | = | - | 9 10 |
9 10 | = | 9 80 | s |
9 80 | s | = | 9 10 |
| s | = | 9 10 | ÷ | 9 80 |
| = | 9 10 | × | 80 9 |
| = | 1 | × | 8 |
| s | = | 8 |