6 13/15+3 7/12- 4 9/20.

6 13/15 + 3 7/12 - 4 9/20 = 6 52/60 + 3 35/60 - 4 27/60 = 9 87/60 - 4 27/60 = 5 60/60 = 6 

1) 6013/15 +3 7/12 = 6 52/60 + 3 35/60=9 87/60=10 27/602) 10 27/60 - 4 9/20 = 10 27/60 - 4 27/60=6