简算:4/5/(3/4-2/5)
问题描述:
简算:4/5/(3/4-2/5)
答
4/5/(3/4-2/5)
=4/5/(15/20-8/20)
=4/5/(7/20)
=4 /5 x(20/7)
=80/35
=16/7