5/9•2 •1/4:20 ;(1•1/2-3/8):7 ;(1-1/2):(1/2-1/3)

5/9•2 •1/4:20= 5/9*1*1/2*1/20=1/9*1/2*1/4=1/72 (1•1/2-3/8):7=(1/2-3/8)*1/7=(4/8-3/8)*1/7=1/8*1/7=1/56 (1-1/2):(1/2-1/3)=1/2:(3/6-2/6)=1/2:1/6=1/2*6/1=6/2=3