8.39÷2和8.39×0.5都表示8.39的一半． ．
÷=； ÷=．
因为A×B=1，所以A=，B=．（A、B≠0） ．
÷7=÷ =38．
× =× = ×= ×0.1=+ = ﹣．
× =× =+ =1.5× =× =1．
=
； ÷
=
．
，B=
．（A、B≠0） ．
÷ =38．
× =
× = ×
= ×0.1=
+ = ﹣
× =
× =
+ =1.5× =
× =1．
粤公网安备 44130202000953号