54.9x0.38的简便计算过程如下.54.9x0.38=(55-0.1)x(0.4-0.02)=55x(0.4-0.02)-0.1x(0.4-0.02)=55x0.4-55x0.02-0.1x0.4+0.1x0.02=22-1.1-0.04+0.002=20.862 扩展资料:1、简便计算中的运算定律 简便计算中的运算定律有加法结合律、加法交换律

54.9x0.38=(55-0.1)x0.38=0.38x55-0.038=20.9-0.038=20.862

54.9x0.38=54.9x(0.4-0.02)=54.9x0.4-54.9x0.02=21.9-1.098=20.862

54.9X0.38=(55-0.1)X(0.4-0.02) =55X0.4-55X0.02-0.1X0.4+0.1X0.02 =22-1.1-0.04+0.002 =20.862

=(55-0.1)x0.38 =55x0.38-0.1*0.38 =20.9-0.38 =20.52

54.9*0.38=5490*38 =(5500-10)*(40-2) =5500*40+5500*(-2)-10*40+10*2 =220000-11000-400+20 =208620 因为开始乘了1000 所以208620要除以1000=20.862 求采纳 谢谢~~~

54.9乘0.38=(55-0.1)*0.38=20.9-0.038=20.862

54.9x0.38=(55-0.1)*2*0.19=(110-0.2)*0.19=20.9-0.038=20.862

20.862 解析: 54.9*0.38 =(55-0.1)*0.38 =55*0.38-0.1*0.38 =20.9-0.038 =20.862

54.9*0.19*2