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问题: 1/2+1/6+1/12+1/20+******+1/9900+?

1/2+1/6+1/12+1/20+******+1/9900+?

解答:

1/2+1/6+1/12+1/20+******+1/9900
=1/(1*2)+1/(2*3)+1/(3*4)+1/(4*5)+……+1/(99*100)
=(1-1/2)+(1/2-1/3)+(1/3-1/4)+(1/4-1/5)+……+(1/99-1/100)
=1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+……+1/99-1/100
=1-1/100
=99/100