Вычесли 1/6 +2/7 11/18 -5/12 8 целых 17/20 - 6 целых 7/10 срочно
1/6 + 2/7 = 7/42 + 12/42 = 19/42 11/18 - 5/12 = 22/36 - 15/36 = 7/36 8 17/20 - 6 7/10 = 8 17/20 - 6 14/20 = 2 целых 3/20