(3 11/27 - 2 17/18):1 23/27+ 3 3/5: 3 = 1 9/20
1) 3 11/27-2 17/18 = 3 22/54 - 2 51/54 = 2 76/54 -2 51/54 = 25/54
2) 25/54: 1 23/27 =25/54* 27/50 = 1/4
3) 3 3/5:3 = 18/5:3/1= 18/5*1/3 = 6/5 = 1 1/5
4) 1/4+1 1/5 = 5/20+ 1 4/20 = 1 9/20
(я надеюсь Вы умеете сокращать)