一个数缩小2倍,再缩小2倍,再缩小4倍得数是20,这个数是 .
12: =0.375=45÷ = :56=.
15:90= %==6÷ = :12.
=:0.5= ÷ .
:8===9÷ =27: .
=== ÷5=.