怎么简算?

来源:学生作业学帮网 编辑:学帮网 时间:2024/05/22 15:36:44

怎么简算?
 

去掉括号.
11/20 + 7/13 - 3/20 -7/13
= 11/20 - 3/20 + 7/13 - 7/13
= ( 11/20 - 3/20) + (7/13 - 7/13)
=8/20 + 0
=4/10
=2/5

收起

11/20+7/13-(3/20+7/13)
=11/20+3/20+7/13-7/13
=11/20+3/20
=14/20