五年级向希望工程捐款x,比四年级多45元,四年级和五年级共捐款多少元?列式为 .
9÷ =0.6= :20=30: .
= :15==6÷ = (填小数)
:8=15÷ ==9: .
==12÷ = :20= (小数)
15÷ === %= (小数)