计算(﹣5)-(+3)+(-9)﹣(﹣7)+1/2的值为(

问题描述:

计算(﹣5)-(+3)+(-9)﹣(﹣7)+1/2的值为(

=7+1/2-(5+3+9) =7.5-17 =-9.5

(﹣5)-(+3)+(-9)﹣(﹣7)+1/2=-19/2