3千克50克= 千克,3分40秒= 秒.
==6﹣ = ÷= 折.
:5=72: =18:15== % .
=0.3: = %= (填小数)= 折= 成.
:12= ÷8=0.75== %
÷12=25%=9÷ = : =.