1⼀2+1⼀6+1⼀12+1⼀20+......+1⼀90简便计算。

2025-02-01 15:42:08
推荐回答(2个)
回答1:

答:1/2+1/6+1/12+1/20+......+1/90
=1/2+(1/2-1/3)+(1/3-1/4)+(1/4-1/5)+...+(1/9-1/10)
=1/2+1/2-1/10
=1-1/10
=9/10

回答2:

1/2+1/6+1/12+1/20+......+1/90
=1/2+(1/2-1/3)+(1/3-1/4)+(1/4-1/5)+...+(1/9-1/10)
=1/2+1/2-1/10
=1-1/10
=9/10