[4又5/9-（2又2/5+0.64）/3又1/25+5/6]*4.5
=[41/9-(12/5+16/25)/(76/25)+5/6]*9/2
=[41/9-76/25/(76/25)+5/6]*9/2
=[41/9-1+5/6]*9/2
=[32/9+5/6]*9/2
=79/18*9/2
=79/4