0.25×2.4=0.25×（2+0.4）=0.25×2+0.25×0.4=0.5+0.1=0.6
2.4*0.25=2*0.25+0.4*0.25=0.5+0.1=0.6
2.4乘以0.25=0.6x4x0.25=0.6x1=0.6
2.4*0.25=（0.25*4）*0.6=1*0.6=0.6
