6.84.2+5.8+5.85.8怎么巧算

分类: 作业答案 • 2022-04-24 19:29:45

问题描述：

6.8*4.2+5.8+5.8*5.8怎么巧算

答

6.8*4.2+5.8+5.8*5.8
=6.8x4.2+5.8x(1+5.8)
=6.8x4.2+5.8x6.8
=6.8x(4.2+5.8)
=6.8x11
=6.8x(10+1)
=6.8x10+6.8x1
=68x6.8
=74.8

6.8*4.2+5.8+5.8*5.8怎么巧算