Question

1.21ⅹ1.8-8.2ⅹO.21怎么简便计算？

这道题怎么简便计算

Answer 1

由题目要求可得式子1.21*1.8-8.2*0.21，在这个式子中可以将1.21拆成1+0.21，1.21*1.8-8.2*0.21＝(1+0.21)*1.8-8.2*0.21＝1*1.8+0.21*1.8-8.2*0.21＝18+0.21*(1.8+8.2)＝18+0.21*10＝18+2.1＝20.1

Answer 2

中间减号应为加号才可简便
1.21X1.8+8.2X0.21
=（1+0.21）X1.8+8.2X0.21
=1.8+021Ⅹ1.8+8.2X0.21
=1.8+0.21X（1.8+8.2）
=1.8+0.21X10
=1.8+2.1
=3.9

Answer 3

=(1+0.21)×1.8－8.2×0.21
=1×1.8+0.21×1.8－8.2×0.21
=1.8+0.21×(1.8－8.2)
=1.8－3.6×0.21
=3.6×0.5－3.6×0.21
=3.6×(0.5－0.21)
=3.6×(0.3－0.01)
=1.08－0.036
=1.046

Answer 4

根据你的这个题目意思，没有什么特别的简单方法，直接计算即可，
1.21✘1.8-8.2✘0.21
=2.178-1.722
=0.456
以上仅供你参考一下，

Answer 5

1.21×1.8-8.2×0.21
=1×1.8+0.21×1.8-8.2×0.21
=1.8-（8.2-1.8）×0.21
=1.8-6.4×0.21
=1.8-6.4×0.2-6.4×0.01
=1.8-1.28-0.064
=0.52-0.064
=0.456