как решить (5 5/9 - 6,8):(2 13/30 - 2 1/12) *3,6

(5 5/9 - 6,8):(2 13/30 - 2 1/12) *3,6 = (50/9 - 68/10):(73/30 - 25/12)*36/10 = (500/90-622/90):(146/60 - 150/60)*36/10 = (-122/90):(-4/60)*36/10=(61/45*15/1)*36/10=61/3*36/10=732/10=73,2