Question

2.5*0.8-0.5*1.8的简便算法

Answer 1

这个题目很简单：原式=0.5x5x0.8—0.5x1.8=0.5x（5x0.8—1.8）=0.5x2.2=0.5x（2+0.2）=0.5x2+0.5x0.2=1+0.1=1.1

Answer 2

2.5*0.8-0.5*1.8
=2.5×0.8-0.5×（1+0.8）
=2.5×0.8-0.5×1-0.5×0.8
=（2.5×0.8-0.5×0.8）-0.5×1
=（2.5-0.5）×0.8-0.5
=2×0.8-0.5
=1.6-0.5
=1.1