(7/8-3/4)÷(12.5×40%)
=1/8÷(12.5×0.4)
=0.125÷5
=0.025
答：商是0.025
这个数=0.3÷（2/5-1/3）=9/2
9/2×7/9=7/2=3.5
答：这个数的9分之7是3.5