(9又7分之2+7又9分之2)/(5/7+5/9)

问题描述:

(9又7分之2+7又9分之2)/(5/7+5/9)

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