Question

1.21ⅹ1.8-8.2ⅹO.21怎么简便计算？

这道题怎么简便计算

Answer 1

你问：1.21ⅹ1.8-8.2ⅹO.21怎么简便计算？

这个题目怎么计算也不如用计算器算简便！

Answer 2

1.21ⅹ1.8-8.2ⅹO.21怎么简便计算？
=(1+0.21)×1.8-8.2×0.21
=1×1.8+0.21×1.8-8.2×0.21
=1.8-0.21×(8.2-1.8)
=1.8-0.21×6.4
=1.8-0.21×(6+0.4)
=1.8-0.21×6-0.21×0.4
=1.8-1.26-0.084
=0.456

Answer 3

1.21*1.8-8.2*0.21
=（1+0.21）*1.8-8.2*0.21
=1.8+0.21*1.8-8.2*0.21
=1.8+0.21*（1.8-8.2）
=1.8-0.21*6.4
=1.8-1.344
=0.456
这是最简便的方法

Answer 4

1.21×1.8-8.2×0.21简便运算：

1.21×1.8-8.2×0.21

=(1+0.21)×1.8-8.2×0.21

=1.8+1.8×0.21-8.2×0.21

=1.8-(8.2-1.8)×0.21

=1.8-6.4×0.21

=1.8-1.344

=0.456

Answer 5

先观察。1.21＝1+0.21，8.2＝10-1.8。
所以，
1.21×1.8-8.2×0.21
＝(1+0.21)×1.8-(10-1.8)×0.21
＝1.8+0.21×1.8-2.1+1.8×0.21
＝1.8-2.1+1.8×0.21×2
＝0.456