1\/2+5\/6+11\/12+…+109\/110= 简便计算!
1\/2+5\/6+11\/12+…+109\/110 =1-1\/2+1-1\/6+1-1\/12+...+1-1\/110 =（1+1+1+...+1）-（1\/2+1\/6+1\/12+...+1\/110）=（1+1+1+...+1）-[1\/(1x2)+1\/(2x3)+1\/(3x4)+...+1\/(10x11)]=10-(1-1\/2+1\/2-1\/3+1\/3-1\/4+...+1\/10-1\/11)=10-(1-1...
1\/2+5\/6+11\/12+19\/20的简单算法
=(1\/2+1\/2)+(1\/3+2\/3)+(1\/4+3\/4)+1\/5 =3.2 也就是3又1\/5
1\/2+5\/6+11\/12+19\/20+29\/30+…+379\/380简便方法怎么算?
2=1*2,6=2*3,12=3*4,20=4*5……每一项写成 （n*（n+1）-1）\/（n*（n+1）），这个是可以拆的，可能需要一点经验：=1-1\/（n*（n+1））=1-（1\/n-1\/（n+1））=1-1\/n+1\/（n+1）把整个数列重新写一下就变成了：（1-1\/1+1\/2）+（1-1\/2+1\/3）+（1-1\/3+1\/4...
1\/2+5\/6+11\/12+19\/20+…+9899\/9900等于多少?
解，设a1=2，a2=6，a3=12，a4=20，，，a2-a1=2x2，a3-a2=3x2，a4-a3=4x3，，，则an=n(n+1)，则1\/an=1\/n-1\/(n+1)1\/9900=1\/99-1\/100=1\/a99 则1\/2+5\/6+11\/12+19\/20+，，，+9899\/9900 =(1-1\/2)+(1-1\/6)，，，+(1-1\/9900)=99-(1-1\/2+1\/2-1\/3+，，...
1\/2+5\/6+11\/12+19\/20+29\/30+41\/42简便算法
每个加数都写成（1-一个数）原式=6-（1\/2+1\/6+1\/12+...1\/42)1\/6=1\/2-1\/3 1\/12=1\/3-1\/4 ... 1\/42=1\/6-1\/7
1\/2+5\/6+11\/12+19\/20+29\/30+41\/42+55\/56怎么简算
解: 1\/2+5\/6+11\/12+19\/20+29\/30+41\/42+55\/56 =1\/2+6-1\/6-1\/12-1\/30-1\/42-1\/56 =6+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)=6+1\/8 =6又1\/8
2分之1+6分之5+12分之11+20分之19+。。。+9702分之9701+9900分之9899...
=-(1\/2+1\/6+1\/12+1\/20+...+1\/9702+1\/9900)+99*1 =-[1\/(1*2)+1\/(2*3)++1\/(3*4)+1\/(4*5)+...+1\/(98*99)+1\/(99*100)]+99 .=-1[(1\/1-1\/2)++(1\/2-1\/3)+(1\/3-1\/4)+(1\/4-1\/5)+...+(1\/98-1\/99)+(1\/99-1\/100)]+99 .=-1[(1\/1+...
小学奥数
=99-（1\/2+1\/6+1\/12+。。。+1\/9900）=99-（1-1\/2+1\/2-1\/3+1\/3-1\/4+。。。+1\/99-1\/100）=99-（1-1\/100）=99-1+1\/100 =98又1\/100 请好评 ~在右上角点击【评价】，然后就可以选择【满意，问题已经完美解决】了。如果你认可我的回答，敬请及时采纳，~你的采纳是我前进的...
找规律填数 1\/2,5\/6,11\/12,( ),( ),41\/42,...
1\/2=1-1\/(1*2)5\/6=1-1\/(2*3)11\/12=1-1\/(3*4)19\/20=1-1\/(4*5)29\/30=1-1\/(5*6)41\/42=1-1\/(6*7)……所以19\/20,29\/30为所求
1\/2+5\/6+11\/12+19\/20+29\/30=
1\/2+5\/6+11\/12+19\/20+29\/30 =(1-1\/2)+(1-1\/6)+(1-1\/12)+(1-1\/20)+(1-1\/30)=[1-(1-1\/2)]+[1-(1\/2-1\/3)]+[1-(1\/3-1\/4)]+[1-(1\/4-1\/5)]+[1-(1\/5-1\/6)]=1-1+1\/2+1-1\/2+1\/3+1-1\/3+1\/4+1-1\/4+1\/5+1-1\/5+1\/6 =4+1\/6 =4...
