计算:17/30×31-17/30=?8/9÷【2/5×(2/7×5/2)】=?

问题描述:

计算:17/30×31-17/30=?8/9÷【2/5×(2/7×5/2)】=?

17/30×31-17/30
=17/30×(31-1)
=17/30×30
=17
8/9÷[2/5×(2/7×5/2)]
=8/9÷2/7
=8/9×7/2
=28/9