將分母擴展為10的冪。
通過將分子乘以2，將分母乘以2，將3/5擴展為6/10。
| 3 | = | 3×2 | = | 6 | = | 0.6 |
| 5 | 5×2 | 10 |
通過分子乘以25和分母乘以25將3/4擴展為75/100：
| 3 | = | 3×25 | = | 75 | = | 0.75 |
| 4 | 4×25 | 100 |
通過將分子乘以125和分母乘以125將5/8擴展為625/1000：
| 5 | = | 5×125 | = | 625 | = | 0.625 |
| 8 | 8×125 | 1000 |
2/5 = 2 ÷ 5 = 0.4
1 2/5 = 1 + 2 ÷ 5 = 1.4
計算分數分子的長除法除以分數的分母。
用3除以4的長除法來計算3/4：
| 0.75 | |
| 4 | 3 |
| 0 | |
| 30 | |
| 28 | |
| 20 | |
| 20 | |
| 0 |