1)3/4+1/6=9+2/12=11/12:3/1=2 3/4
5/6-1/2=5-3/6=2/6=1/3:9/1=1/3
2 3/4+1/3=3 1/12
2)(7/15+7/30+4/5)/(2-1/3 -1/2)=(45/30)/(7/6)=9/6×6/7=9/7
