1. 2/5*(3/8-1/5)=7/40
1) 3/8-1/5= 15/40-8/40=7/40 2) 2/5*7/40=14/200=7/100
2. (7/8-1/4)*3/8=
1) 7/8-1/4=7/8-2/8=5/8 2) 5/8*3/8=15/64
3. 2.1:(-4/5)=21/10:(-4/5)=21/10*(-5/4)=-21/8=-5/8
4.(-2/5):(-8)=2/5*1/8=2/40=1/20
5.-2.8*(-1/6)=28/1*1/6=14/6=2 1/3
6.-2.3*1/6=-23/1*1,6=-23/6=3 5/6
7.3-(-6)=3+6=9
8.-2.5-(4)=-6,5
9.-32+(-4)=-36