1/2 + 1/6 + 1/12 +1/20 + 1/30 +1/42等于多少,

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1/2 + 1/6 + 1/12 +1/20 + 1/30 +1/42等于多少,

1/2 + 1/6 + 1/12 +1/20 + 1/30 +1/42等于多少,
1/2 + 1/6 + 1/12 +1/20 + 1/30 +1/42等于多少,

1/2 + 1/6 + 1/12 +1/20 + 1/30 +1/42等于多少,
=(1-1/2)+(1/2-1/3)+(1/3-1/4)+(1/4-1/5)+(1/5-1/6)+(1/6-1/7)
=1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7
=1-1/7
=6/7

答案为:
6/7

1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90+1/110=(1-1/2)+(1/2-1/3)+(1/3-1/4)+...+(1/9-1/10)+(1/10-1/11)=1-1/11=10/11...

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1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90+1/110=(1-1/2)+(1/2-1/3)+(1/3-1/4)+...+(1/9-1/10)+(1/10-1/11)=1-1/11=10/11

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