这样的题目一定是做分母的文章
看1/2=1/(1*2)=1-1/2
1/6=1/(2*3)=1/2-1/3
1/12=1/(3*4)=1/3-1/4
1/20=1/(4*5)=1/4-1/5
1/30=1/(5*6)=1/5-1/6
1/42=1/(6*7)=1/6-1/7
1/56=1/(7*8)=1/7-1/8
现在再来看1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7+1/7-1/8
=1-1/8=7/8
答案很快就知道了.
注意1/(A*B)这样的式子.A和B相差1个数.A小与B就能化成
1/A-1/B的式子
=1-1/8
=7/8本回答被提问者采纳
1\/2+1\/6+1\/12+1\/20+…+1\/56简便计算
1\/2+1\/6+1\/12+1\/20+1\/30+1\/42+1\/56 =(1-1\/2)+(1\/2-1\/3)+(1\/3-1\/4)+(1\/4-1\/5)+(1\/5-1\/6)+(1\/6-1\/7)+(1\/7-1\/8)=1-1\/8 =7\/8
怎样简算“1\/2+1\/6+1\/12+1\/20+1\/30+1\/42+1\/56”
1\/2+1\/6+1\/12+1\/20+1\/30+1\/42+1\/56=?这样的题目一定是做分母的文章 看1\/2=1\/(1*2)=1-1\/2 1\/6=1\/(2*3)=1\/2-1\/3 1\/12=1\/(3*4)=1\/3-1\/4 1\/20=1\/(4*5)=1\/4-1\/5 1\/30=1\/(5*6)=1\/5-1\/6 1\/42=1\/(6*7)=1\/6-1\/7 1\/56=1\/(7*8)=1\/7-1...
2分之1加6分之1加12分之1加20分之1加30分之1加42分之1加56分之1加72...
回答：最基本的裂项求和1\/2=1-1\/21\/6=1\/2-1\/3解:原式=1-1\/2+1\/2-1\/3+……+1\/8-1\/9=1-1\/9=8\/9
1\/2+1\/6+1\/12+1\/20+1\/30+1\/42+1\/56 简算
1\/2+1\/6+1\/12+1\/20+1\/30+1\/42+1\/56 =(1-1\/2)+(1\/2-1\/3)+(1\/3-1\/4)+(1\/4-1\/5)+(1\/5-1\/6)+(1\/6-1\/7)+(1\/7-1\/8)=1-1\/8 =7\/8
怎样简算“1\/2+1\/6+1\/12+1\/20+1\/30+1\/42+1\/56”
1\/2+1\/6+1\/12+1\/20+1\/30+1\/42+1\/56=?这样的题目一定是做分母的文章 看1\/2=1\/(1*2)=1-1\/2 1\/6=1\/(2*3)=1\/2-1\/3 1\/12=1\/(3*4)=1\/3-1\/4 1\/20=1\/(4*5)=1\/4-1\/5 1\/30=1\/(5*6)=1\/5-1\/6 1\/42=1\/(6*7)=1\/6-1\/7 1\/56=1\/(7*8)=1\/7-1...
1\/2+1\/6+1\/12+1\/20+1\/30+1\/42+1\/56=?简算,快
1\/2+1\/6+1\/12+1\/20+1\/30+1\/42+1\/56 =1-1\/2+1\/2-1\/3+1\/3-1\/4+1\/4-1\/5+1\/5-1\/6+1\/6-1\/7+1\/7-1\/8 =1-1\/8 =7\/8 如果对你有帮助，请采纳。谢谢。这可是最先回答的哟。祝进步！！！
简算题1\/2+1\/6+1\/12+1\/20+1\/30+1\/42+1\/56?
1\/2+1\/6+1\/12+1\/20+1\/30+1\/42+1\/56 =1\/2+(1\/2-1\/3)+(1\/3-1\/4)+(1\/4-1\/5)+(1\/5-1\/6)+(1\/6-1\/7)+(1\/7-1\/8)=1\/2+1\/2-1\/3+1\/3-1\/4+1\/4-1\/5+1\/5-1\/6+1\/6-1\/7+1\/7-1\/8 =1\/2-1\/8 =4\/8-1\/8 =3\/8,2,
如何简算1\/2+1\/6+1\/12+1\/30+
如何快速计算1\/2+1\/6+1\/12+1\/30+1\/42+1\/56的和呢？这里有一个简便的方法。首先，我们可以将这些分数重新组合，利用它们之间的相互关系来进行简化。将每个分数写成两个分数的差，如下所示：1\/2 = 1 - 1\/2 1\/6 = 1\/2 - 1\/3 1\/12 = 1\/3 - 1\/4 1\/30 = 1\/5 - 1\/6 1\/42...
...加十二分之十一加二十分之一加三十分之一加四十二分之一加五十六分...
1\/2+1\/6+1\/12+1\/20+1\/30+1\/42+1\/56 =(1-1\/2)+(1\/2-1\/3)+(1\/3-1\/4)+(1\/4-1\/5)+(1\/5-1\/6)+(1\/6-1\/7)+(1\/7-1\/8)=1-1\/8 =7\/8
谁知道这题的简算啊?急
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)有公式为1\/（n+n+1)=(1\/n)-1\/(n+1)∴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\/...
