首页 > 留学知识库

问题: 1/20 1/30 1/42 1/56 1/72 1/90=?

1/20+1/30+1/42+1/56+1/72+1/90=?

解答:

1/4-1/5+1/5-1/6+1/6-1/7+1/7-1/8+1/8-1/9+1/9-1/10=1/4-1/10=0.15