Question

5.7乘以2.2的简便方法？

Answer 1

其中一个两位数化为一位数，比如2.2
5.7×2.2
=5.7×(2+0.2)
=5.7×2+5.7×0.2
=11.4+1.14
=12.54

Answer 2

根据题意可知:
5.7×2.2
＝5.7×(2+0.2)
＝5.7×2+5.7×0.2
＝(5+0.7)×2+5.7×0.2
＝5×2+0.7×2+5.7×0.2
＝10+1.4+5.7×0.2
＝11.4+5.7×0.2
根据2是0.2的10倍，可以知道5.7×0.2＝(5.7×2)÷10＝11.4÷10＝1.14(即小数点后移一位)
因此上式＝11.4+1.14＝12.54

Answer 3

5.7×2.2的简便运算方法应该是把2.2分成2+0.2。那么5.7×2=11.4。5.7×0.2=1.14。11.4+1.14=12.54。所以5.7×2.2，最后的结果就应该是12.54。

Answer 4

=5.7×(2+0.2)=5.7×2+5.7×0.2=11.4+1.14=12.54

Answer 5

5.7×2.2
=5.7×（2+0.2）
=5.7×2+5.7×0.2
=11.4+1.14
=12.54