Question

25.6乘4.2加2.3乘25.6减2.56乘64的简便方法？

Answer 1

解题思路：这是几个乘法式子相加减的混合运算，要求简算，我们不难发现前面两个乘法式子中都有25.6,后面乘法式子中有个2.56,我们可以通过扩大一个因数的倍数然后缩小另一个因数相同的倍数使式子的积不变，使得2.56变成25.6，然后用乘法分配律进行简算，具体计算过程如下
25.6×4.2+2.3×25.6-2.56×64
=25.6×4.2+2.3×25.6-25.6×6.4
=25.6×(4.2+2.3-6.4)
=25.6×0.1
=2.56

Answer 2

原式是，25.6×4.2+2.3×25.6-2.56×64。因为2.56×64＝25.6×6.4。所以原式＝25.6×4.2+25.6×2.3-25.6×6.4＝25.6×（4.2+2.3-6.4）＝2.56

Answer 3

根据题义可列算式如下： 25.6×4.2+2.3×25.6+2.56×64
=25.6×4.2+25.6×2.3-25.6×6.4
=25.6×（4.2+2.3-6.4)
= 25.6×0.1
=2.56
这就是这道题的简便计算。

Answer 4

25.6×4.2+2.3×25.6-2.56×64
【提取25.6】
=25.6×(4.2+2.3-0.1×64)
=25.6×0.1
=2.56

Answer 5

简便运算过程如下
25.6×4.2+2.3×25.6-2.56×64
=25.6×（4.2+2.3-6.4）
=25.6×0.1
=2.56