0.2和 互为倒数,的倒数是 ,方程x+3=4.5的解是 .
= %= ÷20=0.35= :40.
0.75== ÷8= %= 成数.
3÷ =× =5: =1.25=.
= .
x除以y的商是,y与x的比是 .