中括号5-90.5*9.5+2*0.5)中括号/21分之8 简便
问题描述：
中括号5-90.5*9.5+2*0.5)中括号/21分之8 简便
答
=[5-(90+0.5)(10-0.5)+1]/(21/8)
=[5-(900-45+5-0.25)+1]/(21/8)
=-854.75/(21/8)
=（-854.75×8）/21
=-6838/21