igir12370 7 5/12 - 5 9/10=6 + 1 + 5/12 - 5 - 9/10=6 - 5 + 12/12 + 5/12 - 9/10=1 + 17/12 - 9/10=1 + 17*5/12*5 - 9*6/10*6=1 + 85/60 - 54/60=1 + (85-54)/60=1 + 31/60=1 31/60;