1/6+1/12+1/30+1/42+1/56= 要简便算法,

分类: 作业答案 • 2022-01-09 18:04:27

问题描述：

答

1/6+1/12+1/30+1/42+1/56
=1/6*1+1/6*1/2+1/6*1/5+1/6*1/7+1/6*1/8
=1/6*（1+1/2+1/5+1/7+1/8）
=1/6*551/280
=551/1680

答

1/6+1/12+1/30+1/42+1/56=
1/2-1/3+1/3-1/4+1/5-1/6+1/6-1/7+1/7-1/8
=1/2-1/4+1/5-1/8
=13/40

答

原式=1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7+1/7-1/8
=1/2-1/8
=3/8