哥哥跑步的速度比弟弟快,也就是弟弟跑步的速度比哥哥慢20%. .(判断对错)
12÷ == ÷45.
9: ==3÷5.
3÷4==27: = (填小数)= %.
÷4==0.25= :8.
=9÷ = :8== (填小数)