0.325*0.8+0.55/5/4-3/5/8/7
=0.325*0.8+0.55*0.8-3/5×7/8
=(0.325+0.55)×0.8-3/5×7/8
=7/8×0.8-0.6×7/8
=7/8×(0.8-0.6)
=7/8×1/5
=7/40
0.325*0.8+0.55/5/4-3/5/8/7
=0.325*0.8+0.55*0.8-3/5×7/8
=(0.325+0.55)×0.8-3/5×7/8
=7/8×0.8-0.6×7/8
=7/8×(0.8-0.6)
=7/8×1/5
=7/40