原式=1-[（1-1/2）+(1/2-1/3)+(1/3-1/4)+...+(1/8-1/9)+(1/9-1/10)]
=1-(1-1/10)
=1/10
1-1/2+1/6+1/12+1/20+...+1/72+1/90
1个回答
相关问题
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2\1-6\1-12\1-20\1-30\1-42\1-56\1-72\1-90\1
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1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90=
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2/1＋6/1＋12/1＋20/1＋30/1＋42/1＋56/1＋72/1＋90/1
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1/2+1/6+1/12+...1/72+1/90
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简算：1/6+1/12+1/20+1/30+.1/72+1/90
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(1)2/1+6/1+12/1+20/1+30/1+42/1+56/1+72/1+90/1
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1-1/2+1/6+12/1+20/1+24/1+28/1+.+1/72+1/90等于多少?
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计算：1/2+1/6+1/12+1/20+/+1/30+1/42+1/56+1/72+1/90
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计算1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90
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1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90