1. в
2. 2/3 + 1/2 = 4/6+3/6 = 7/6
4целых3/4 - 2целых1/8 = 19/4-17/8 = 38/8 - 17/8 = 21/8
5/6*1целую2/5 = 5/6*7/5 = 7/6 = 1целая1/6
4целых2/3+1целая7/9 = 14/3+16/9 = 42/9+16/9 = 58/9 = 6целых4/9
3.а) (условие)= 27/5*20/3+10/3*27/5 = 9*4+"*9 = 36+18 = 54