| 60 | × | 10 | + | 80 | × | 10 | + | 100 | × | 10 | = | 60 | × | 3 | X | + | 80 | × | 4 | X | + | 100 | × | 5 | X |
| 方程左边 = | 600 | + | 800 | + | 1000 |
| = | 2400 |
| 2400 | = | 60 | × | 3 | X | + | 80 | × | 4 | X | + | 100 | × | 5 | X |
| 方程右边 = | 180 | X | + | 320 | X | + | 500 | X |
| = | 1000 | X |
| 2400 | = | 1000 | X |
| - | 1000 | X | = | - | 2400 |
| 2400 | = | 1000 | X |
| 1000 | X | = | 2400 |
| X | = | 2400 | ÷ | 1000 |
| = | 2400 | × | 1 1000 |
| = | 12 | × | 1 5 |
| X | = | 12 5 |
| X | = | 2.4 |