7/9*(1 целая 1/6-1:1 целая 1/19-1/15)+4 целых 2/5:24Не могу решить!!!!!!!

1 : 1 1/19 = 1 : 20/19 = 19/20 1 1/6 - 19/20 = 7/6 - 19/20= 13/60 13/60 - 1/15 = 3/20 7/9 * 3/20 = 7/60 4 2/5 : 24 = 22/5 : 24 = 11/60 7/60 + 11/60 = 17/60