1/2+1/6+1/12+1/20+1/30+1/42+1/56
=1/1*2+1/2*3+1/3*4+1/4*5+1/5*6+1/6*7+1/7*8
=1/1-1/2+1/2-1/3+1/3-1/4+……+1/7-1/8
=1-1/8
=7/8
1/2+1/6+1/12+1/20+1/30+1/42+1/56
8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=?
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1/2+1/6+1/12+1/20+1/30+1/42+1/56
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2/1+6/1+12/1+20/1+30/1+42/1+56/1=?
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2/1+6/1+12/1+20/1+30/1+42/1+56/1=
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1／2 + 1／6 + 1／12 + 1／20 + 1／30+ 1／42 + 1／56 + 1／72＝
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1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72=?
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1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72=?
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1/6+1/12+1/20+1/30+1/42+1/56=多少
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1/2+1/6+1/12+1/20+1/30+1/42+1/56=?简便运算.
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1/2+1/6+1/12+1/20+1/30+1/42+1/56=?(要算式）