变形后应用乘法分配律可以使计算简便。14.4x0.42+1.44x3.8-0.4x18.8=14.4x0.42+14.4x0.38-0.4x18=（0.42+0.38）x14.4-0.4x18.8=0.8x14.4-0.4x18.8=0.8x14.4-0.8x9.4=0.8x（14.4-9.4）=0.8x5=4
