1.) 5/6 - 9/12 = 10/12 - 9/12 = 1/12
2.) 15/16 - 3/4 = 15/16 - 12/16 = 3/16
3.) 19/21 - 1/7 = 19/21 - 3/21 = 16/21
4.) 5/6 - 3/8 = 20/24 - 9/24 = 11/24
5.) 5/9 - 7/18 = 10/18 - 7/18 = 3/18 = 1/6
6.) 7/8 - 5/7 = 49/56 - 40/56 = 9/56
