1) 1 целая 7/9 * (15/32 : 1 целая 19/36) = 1 7/9 * (15/32 * 36/55) = 16/9 * 27/88 = 6/11

2) 3 целых 3/4 : 3/8 : 1 целая 3/7 = 15/4 : 8/3 : 7/10 = 7

3) 3 целых 4/7 : (1 целая 1/7 * 2/3) = 3 4/7 : (8/7 * 2/3) = 25/7 : 21/16 = 75/16 = 4 целых 11/16