Question

2.5×2.3+1.9的简便计算？

Answer 1

2.5*2.3+1.9
=2.5*（2.4-0.1）+1.9
=2.5*2.4-2.5*0.1+1.9
=2.5*0.8*3-0.25+1.9
=2*3-0.25+1.9
=6+1.9-0.25
=7.9-0.25
=7.65

Answer 2

可以采用分配律结合加法的方法来简化这个表达式，即：
2.5 × 2.3 + 1.9 = (2.5 × 2) + (2.5 × 0.3) + 1.9
= 5 + 0.75 + 1.9 (将小数 0.3 转化成分数 3/10)
= 7.65
因此，2.5×2.3+1.9 的简便计算结果为 7.65。

Answer 3

2.5×2.3+1.9
=2.5x（1.9+0.4）+1.9
=2.5×1.9+1+1.9
=（2-0.1）x（2.5+1）+1
=（2-0.1）x3.5+1
=7-0.35+1
=7.65
把2.3分成1.9和0.4达到简便计算目的。

Answer 4

2.5ⅹ2.3+1.9
=2.5ⅹ(1.9+0.4)+1.9
=2.5x1.9+1+1.9
=(2-0.1)x(2.5+1)+1
=(2-0.1)ⅹ3.5+1
=7-0.35+1
=7.65