12分之5乘4.69加3.21乘10又12分之5加7.9除以1又7分之5

题目

12分之5乘4.69加3.21乘10又12分之5加7.9除以1又7分之5

答案

(5/12)×4.69+3.21×(125/12)+7.9÷(12/7)
=(5/12)×4.69+3.21×(125/12)+7.9×(7/12)
=(5×4.69+3.21×125+7.9×7)/12
=[5×(4.69+80.25)+55.3]/12
=480/12
=40