a: =-5/11-6/11+1=1-1=0
b: =2/3-2/3+5/7=5/7
c: =-1/4+5/8-3/8=-1/4+1/4=0
d: =3/4(7/25+18/25)=3/4
e: =7/5(8/19+12/19-1/19)=7/5
f: =-3/5(5/7+3/7+6/7)=-3/5*2=-6/5
g: =10+2/9+2+2/5-7-2/9
=5+2/5
=5,4
h: =6+3/10-3-4/7-2-3/10
=1-4/7=3/7
j: =7+4/9+4+7/11-3-4/9
=8+7/11
=95/11