1/30-（-2/3+3/5）÷（-2）=1/30-(-1/15)*(-1/2)=1/30-1/30=0-（2/13-1/3-1/6）×78=-（2/13×78-1/3×78-1/6×78)=-(12-26-13)=2765％（y-1）=37％（y+1）-0.820.65y-0.65=0.37y+0.37-0.820.65y-0.37y=0.65+0.37-0....