18的计数单位 ,0.18的计数单位是 .
=5:8= %= ÷32=0.625.
4÷ == :15== %=( 小数)
12: ==0.6=48÷ .
:30=30÷ === (小数)= 折.
75%= (小数)= (成数)= (折数)= : .