(3 11/27 - 2 17/18) : 1 23/27 + 3 3/5 : 3 = 1 9/20
1) 3 11/27 - 2 17/18 = 92/27 - 53/18 = (184-159)/54 = 25/54
2) 25/54 : 1 23/27 = 25/54 : 50/27 = 25/54 * 27/50 = 1/4
3) 3 3/5 : 3 = 18/5 : 3/1 = 18/5 * 1/3 = 6/5
4) 1/4 + 6/5 = (5+24)/20 = 29/20 = 1 9/20