1) (4,5 + (23/6)) * 0,6 = ((9/2) + (23/6)) / (3/5) = (25/3) * (3/5) = 25/5 = 5
2) 3,7 / ((11/9) - 0,4) = (37/10) / ((11/9) - (2/5)) = (37/10) / (37/45) = 9 / 2 = 4,5
3) (4 : (4/7) * 0,3) / (2,88 : 4,8) = (4 * (7/4) * (3/10)) / 0,6 = (7 * (3/10)) / (3/5) = 7 / 2 = 3,5
4) (0,5 + (1/18)) / (((7/6) - (7/18)) : 2,8) = ((1/2) + (1/18)) / ((7/9) : (14/5)) = (5/9) / ((7/9) * (5/14)) = (5/9) / ((1/9 * (5/2)) = (5/9) / (5/18) = 2