Question

7.5x0.8＋1.2x12.5＋2.5x1.6的简便算法？

Answer 1

7.5x0.8＋1.2x12.5＋2.5x1.6
=15x0.5x0.8+1.2x25x0.5+5x0.5x1.6
=0.5x12+0.5x30+0.5x8
=0.5x（12+30+8）
=0.5x50
=25

Answer 2

7.5乘以0.8等于2.5乘以2.4.12.5乘以1.2等于2.5乘以6.2.4+6+1.6等于10.再乘以2.5等于25

Answer 3

7.5x0.8＋1.2x12.5＋2.5x1.6的简便算法
可以提取公因式 2.5 得到式子为

2.5×3x0.8＋2.5×5x1.2＋2.5x1.6
=2.5×（2.4+6+1.6）
=2.5×10
=25

Answer 4

解:
原式
=2.5x3x0.8+1.2x5x2.5+2.5x1.6
=2.5x2.4+2.5x6+2.5x1.6
=2.5x(2.4+6+1.6)
=2.5x10
=25

方法:
构造后利用乘法分配律实现简便计算。

Answer 5

根据题目的简便计算，可以这样计算。
7.5×0.8＋1.2×12.5＋2.5×1.6
=7.5×0.8＋2.5×2×0.8＋1.2×12.5
=(7.5＋5)×0.8＋1.2×12.5
=12.5×0.8＋1.2×12.5
=12.5×(0.8＋1.2)
=12.5×2
=25