1、第一种方法:
54.9×0.38
=55x0.38-0.1x0.38
=20.9-0.038
=20.862
2、第二种方法:
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
谢谢你的关注
1、第一种方法:
54.9×0.38
=55x0.38-0.1x0.38
=20.9-0.038
=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
54.9×0.38
=55×0.38-0.l×0.38
=20.9-0.038
=20.869