在中(y不为0),当y= 时,=x;当x= 时,=1.
:10== ÷20= %=0.7=.
= ÷ === (小数)= (百分数)= (成数)
0.16==2÷ =8: = %
0.75==6÷( )=12:( )=( )%
0.25== :16=5÷ = %