1) 11/12 - 1/20 - 1/30
11/12 - 1/20 = 220/240 - 12/240 = 208/240 = 13/15
13/15 - 1/30 = 26/30 - 1/30 = 25/30 = 5/6
2/3 - 5/24 = 16/24 - 5/24 = 11/24
2) 2/3 - 5/24 - 3/10
11/24 - 3/10 = 110/240 - 72/240 = 38/240 = 19/120
3) 4/5 - 4/45 - 7/25
4/5 - 4/45 = 36/45 - 4/45 = 32/45
32/45 - 7/25 = 160/225 - 63/225 = 97/225
