二分之一除以中括号1-1反括号三分之一加九分之五反括号中括号简便计算怎么算？

Question

如题所述

Answer 1

1/2÷[1-(1/3+5/9)]
=1/2÷[1-(3/9+5/9)]
=1/2÷[1-8/9]
=1/2÷1/9
=1/2×9
=9/2
=4.5