简便计算 (9右2/7+7右2/9)除(5/7+5/9)=

问题描述:

简便计算 (9右2/7+7右2/9)除(5/7+5/9)=
要详解谢谢

=(65/7+65/9)÷(5/7+5/9)
=(13×5/7+13×5/9)÷(5/7+5/9)
=13×(5/7+5/9)÷(5/7+5/9)
=13