1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90
＝1-1/2+1/2-1/3+1/3-1/4+……1/9-1/10 （除了1与1/10,两两抵消）
＝1-1/10
＝9/10
呵呵,加油!不懂再问,诚答!
1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90=1怎么算简便?
6个回答
相关问题
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1/2+1/6+1/20+1/30+1/42+1/56+1/72=怎么算简便?
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1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90简便计算
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2/1+6/1+12/1+20/1+30/1+42/1+56/1+72/1+90/1,简便运算,
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简算：1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90
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简算6/1+12/1+20/1+30/1+42/1+56/1+72/1+90/1
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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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1/6+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=?