(3又3/5-1又5/7)*11又2/3/(2又2/9-2又1/18)
=(18/5-12/7)*35/3/(20/9-37/18)
=(6*7-4*5)/(77/18)
=(42-20)/(77/18)
=22/(77/18)
=22*(18/77)
=(2*18)/11
=36/11