1、 7.5*3.1/2.5*100=7.5/2.5*3.1*100=3*3100=93002、36.5*6.2+28*0.365+3.65=36.5*6.2+2.8*3.65+3.65=3.65*（6.2+2.8+1）=3.65*1.=36.5 3、999.9*599.9+199.9=1000×599+0.1×599.9+200-0.1=5990+59.9+200-0.1=6049...