从18的约数中选4个数,组成一个比例是 .
1= ÷10=24: = %= [填小数].
12÷ = :20==0.8= %
将分数1写成两个数相除的式子:1 .
:16=15÷ == %= (填小数)
÷ = :16=5÷ = %=0.25.