1. (1/8+2/9-1/4)×5 1/7:(7/9-2/3+1/6)= -9/35
(1/8+2/9-1/4)=9/72+8/72=17/72-18/72= -1/72
-1/72×5 1/7= -1/72×36/7= -1/14
(7/9-2/3+1/6)=14/18-12/18+3/18)=5/18
-1/14 :5/18=(-1×18):(-14×5)= -9/35
2. (10 3 /4-12-11/5)+4/9+2 1 /6+3 1 /4: 5 1/5=-4/5 (10 3/4-12-11/5)=(3/4-2-11/5)=(-1 1/4- 11 /5)=
=(-5/4-11/5)=(-25-44)/20=-69/20= -3 9/20
3 1/4:5 1 /5=13/4 : 26 /5=(13×5):(4×25)=13/20
-3 9/20 +4/9+2 1/6+13/20=(-69/20+13/20)+
+4 /9+2 1/6 = -56/20+(4 /9 +2 1/6)= -56/20+
+(8 /18+36/18)=-56 /20 +44/18=-2 16/20 +2 =
=-16/20=- 4 /5