0.25×0.4简便运算为:0.25×0.4=0.5×0.5×0.4=0.5×2=1
0.25× 0.4=25×0.01×4×0.1=25×4×0.01×0.1=100×0.01× 0.1=0.1
0.25*0.4=0.1
