1/5 / 6/25-2/7*7/32=1/5*6/25-1/16=5/6-1/16=80/96-6/96=74/96
1/5除以6/25-2/7*7/32=5/6-1/16=37/48
=1/5*25/6-2/7*7/32=5/6-1/16=40/48-3/48=37/48
