Question

1.21ⅹ1.8-8.2ⅹO.21怎么简便计算？

这道题怎么简便计算

Answer 1

这道题可以简便计算，运用四则运算法则，先将1.21变化成1+0.21，再分别乘以1.8,再提取公共项0.21后，用8.2减1.8求差后再乘以0.21，再与1.8相加即可。解题思路如下: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=1.8-(8.2-1.8)*0.21=1.8-6.4*0.21=1.8-1.344=0.456

Answer 2

原式=(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

1.21x1.8-8.2x0.21=(1+0.21)x1.8-8.2x0.21=1.8+0.21x1.8-8.2x0.21=1.8-(8.2-1.8)x0.21=1.8-6.4x0.21=1.8-(6+0.4)0.21=1.8-(1.26+0.084)=1.8-1.344=0.456

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

1.21x1.8-8.2x0.21
=（1+0.21）x1.8-8.2x0.21
=1.8+1.8x0.21-8.2x0.21
=1.8+0.21（1.8-8.2)
=1.8+0.21x（-6.4）
=1.8-1.344
=0.456