1) -2+1 (7/8)=-1(8/8)+1(7/8)=-1/8=
2) -1+2(1/9)=-9/9+1(10/9)=1(1/9)
3) -4+3(1/2)=-3(2/2)+3(1/2)=-1/2
4)-5/7+4/7=-1/7
5) -5/8+7/8=2/8=1/4
6) -1/6+1=-1/6+6/6=5/6
7) 5/12-1/12=4/12=1/3
8) 7/15-11/15=-4/15
9) 5/16-1/6=(5/16)*6-(1/6)*16=(30-16)/96=14/96=7/48