8.72*45.8/8.72/45.8*8.72 =8.72*45.8/45.8*8.72/8.72=8.72
1.1/[(20+9.744/2.4)*0.5-1.03]=1.1/[(20+4.06)*0.5-1.03]=1.1/(12.03-1.03)=1.1/11=0.1
[19+1.9*(3.8-0.38*0.5/0.05)]/0.38 =[19+1.9*(3.8-3.8)]/0.38=19/0.38=50
[27*4.5+8/0.6]-[120-(40*0.25+25/0.5)*2]*1999=[121.5+40/3]-[120-(10+50)*2]*1999=[121.5+40/3]-0=134.83(约等于）