Question

下列各题怎样简便就怎样算．3.7×1.4×0.05 72×0.81+10.4 1.4×25+3.45 1.5×102 1.25×0.7×0.8

下列各题怎样简便就怎样算．3.7×1.4×0.05 72×0.81+10.4 1.4×25+3.45 1.5×102 1.25×0.7×0.8 2.7×3.7+0.37×73 8.7×99 0.8×（12.5-1.25） 1.25×0.4×80×2.5．

Answer 1

3.7×1.4×0.05 =3.7×（1.4×0.05） =3.7×0.07 =0.259 72×0.81+10.4 =58.32+10.4 =68.72 1.4×25+3.45 =（1+0.4）×25+3.45 =25+0.4×25+3.45 =25+10+3.45 =35+3.45 =38.45 1.5×102 =1.5×（100+2） =1.5×100+1.5×2 =150+3 =153 1.25×0.7×0.8 =1.25×0.8×0.7 =1×0.7 =0.7 2.7×3.7+0.37×73 =2.7×3.7+3.7×7.3 =（2.7+7.3）×3.7 =10×3.7 =37 8.7×99 =8.7×（100-1） =8.7×100-8.7 =870-8.7 =861.3 0.8×（12.5-1.25） =0.8×12.5-0.8×1.25 =10-1 =9 1.25×0.4×80×2.5 =（1.25×80）×（0.4×2.5） =100×1 =100