5/9-7/15*5/7-2/3怎么简算
问题描述:
5/9-7/15*5/7-2/3怎么简算
答
5/9-7/15*5/7-2/3
=5/9-1/3-2/3
=5/9-(1/3+2/3)
=5/9-1
=﹣4/9