3 3/9 : 9/4 = 30/9 * 4/9 = (10*4)/(9*3) = 40/27 = 1 целая 13/27
4 3/8 : 5/16 = 35/8 * 16/5 = (7*2)/(1*1) = 14
4/7 * 5/14 - 3/5 = - 97/245
1) 4/7 * 5/14 = (2*5)/(7*7) = 10/49
2) 10/49 - 3/5 = 50/245 - 147/245 = - 97/245
5 1/5 - 3/5 : 2/15 = 7/10
1) 3/5 : 2/15 = 3/5 * 15/2 = 45/10
2) 5 1/5 - 9/2 = 26/5 - 45/10 = 52/10 - 45/10 = 7/10
2 1/9 : 19/18 = 19/9 * 18/19 = 18/9 = 2