把80平均分成4份,每份是 ,计算时你想到的乘法口诀是 .
= :35=5:7= ÷21=.
== ÷20=6: = %= 折.
÷15=0.8== %= 折.
1﹣1× =0 ÷ == : =75%
: =0.125= %==.