2/5x4+1/5x2/13+2/5x12/13 简便算法

分类: 作业答案 • 2022-01-07 12:06:02

问题描述：

答

2/5x4+1/5x2/13+2/5x12/13
=2/5x4+2/5x1/13+2/5x12/13
=2/5x(4+1/13+12/13)
=2
因为1/5x2/13=2/5x1/13