小民放学排队上阵,从前往后数他是第5个,从后往前数是他是第7个,这一排一共有 个同学.
=9÷ = :8== (填小数)
3: ==15÷ = ×= (小数).
5÷20==4: = :12= %= (填小数)
÷20=12: ==0.8= %.
= : =15÷ ==0.6.