Question

54.9×0.38的简便运算

Answer 1

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

Answer 2

54.9×0.38
=（55-0.1）×（0.4-0.02）
=55×0.4-55×0.02-0.1×0.4+0.1×0.02
=22-1.1-0.04+0.002=20.862
=20.862