1. 1/3-1/9 2. 10/21-1/3 3. 14/15-3/5 4. 17/18-1/95. 4/9-13/456. 1/3-7/30​

1. 1/3-1/9＝3/9-1/9＝2/9

2. 10/21-1/3＝10/21-7/21＝3/21＝1/7

3. 14/15-3/5＝14/15-15/15＝-1/15

4. 17/18-1/9＝17/18-2/18＝15/18＝5/6

5. 4/9-13/45＝20/45-13/45＝7/45

6. 1/3-7/30＝10/30-7/30＝3/30＝1/10