原式=（32/7-15/4）÷（4/7+2/3)*5/6
=(32/7*5/6-15/4*5/6)÷（4/7+2/3)
=（80/21-15/8）÷26/21
=80/21*21/26-15/8*21/26
=40/13-105/104
=320/104-105/104
=215/104