(9*2/7+7*2/9)/(5/7+5/9)的简便运算

问题描述:

(9*2/7+7*2/9)/(5/7+5/9)的简便运算

(9又2/7+7又2/9)/(5/7+5\9)
=(65/7+65/9)/(5/7+5/9)
=[13*(5/7+5/9)]/(5/7+5/9)
=13