9/5×25%+5/1×4/1-0.2=1.8 x 0.25 +20 -0.2=2x0.9x0.25 +20-0.2=0.9x0.5 +20-0.2=0.45 +20-0.2=20.25
5/9×25%+1/5×1/4-0.2=5/9×1/4+1/5×1/4-1/5=(5/9+1/5)×1/4-1/5=34/45×1/4-1/5=17/90-1/5=-1/90
