简便计算.0.46*0.4*2.5= 8.4*0.26+1.27= 0.98*42= 4.5*2.7+4.5*5.3= 1.82*1.25+1.8*0.125 =

0.46*0.4*2.5= 0.46*(0.4*2.5)=0.46*1=0.46
8.4*0.26+1.27= 8.4(0.25+0.01)+1.27=8.4*0.25+8.4*0.01+1.27=2.1*4*0.25+0.084+1.27
=2.1+0.084+1.27=3.454
0.98*42= (1-0.02)*42=42-0.84=41.16
4.5*2.7+4.5*5.3=4.5*(2.7+5.3)=4.5*8=36
1.82*1.25+1.8*0.125 =1.82*1.25+0.18*1.25=1.25*(1.82+0.18)=1.25*2=2.5