1\/2+1\/6+1\/12+1\/20+1\/30=简便计算。
1\/2+1\/6+1\/12+1\/20+1\/30简便计算结果为5\/6。解：1\/2+1\/6+1\/12+1\/20+1\/30 =1\/(1x2)+1\/(2x3)+1\/(3x4)+1\/(4x5)+1\/(5x6)=(1-1\/2)+(1\/2-1\/3)+(1\/3-1\/4)+(1\/4-1\/5)+(1\/5-1\/6)=1-1\/2+1\/2-1\/3+1\/3-1\/4+1\/4-1\/5+1\/5-1\/6 =1-1\/6 ...
1\/2+1\/6+1\/12+1\/20+1\/30=简便计算?
1\/2+1\/6+1\/12+1\/20+1\/30 =30\/60+10\/60+5\/60+3\/60+2\/60 =(30+10+5+3+2)\/60 =50\/60 =5\/6
“1\/2+1\/6+1\/12+1\/20+1\/30”怎样用简便方法计算?
简便计算 1\/2+1\/6+1\/12+1\/20+1\/30 =1\/（1x2）+1\/（2x3）+1\/（3x4）+1\/（4x5）+1\/（5x6）=1-1\/2+1\/2-1\/3+1\/3-1\/4+1\/4-1\/5+1\/5-1\/6 =1-1\/6 =5\/6
1\/2+1\/6+1\/12+1\/20+1\/30怎样用简便方法计算
裂项法，这是分解与组合思想在数列求和中的具体应用。是将数列中的每项（通项）分解，然后重新组合，使之能消去一些项，最终达到求和的目的。 通项分解（裂项）倍数的关系。二、其他裂项法公式：
1\/2+1\/6+1\/12+1\/20+1\/30怎么简便算啊
这种题型有一个固定的方法：裂项相加法（把一个项裂开成两个项）解：1\/2+1\/6+1\/12+1\/20+1\/30 =1\/(1×2)+1\/(2×3)+1\/(3×4)+1\/(4×5)+1\/(5×6)=1\/1-1\/2+1\/2-1\/3+1\/3-1\/4+1\/4-1\/5+1\/5-1\/6 =1-1\/6 =1\/5 ...
...加12分之一加20分之一加30分之一 一步一步算, 简便计算
1\/2+1\/6+1\/12+1\/20+1\/30 =30\/60+10\/60+5\/60+3\/60+2\/60 =50\/60 =5\/6
1\/2+1\/6+1\/12+1\/20+1\/30+...?
1\/2+1\/6+1\/12+1\/20+1\/30+.+1\/9900简便运算过程如 1\/2+1\/6+1\/12+1\/20+1\/30+...+1\/9900 =1\/1*2+1\/2*3+1\/3*4+1\/4*5+1\/5*6+...+1\/99*100 =1-1\/2+1\/2-1\/3+1\/3-1\/4+1\/4-1\/5+1\/5-1\/6+1\/6-...-1\/99+1\/99-1\/100 =1-1\/100 =99\/100 所以1...
二分之一加六分之一加十二分之十一加二十分之一加三十分之一加四十二...
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
1\/2+1\/6+1\/12+1\/20+1\/30+1\/42+1\/56+1\/72+1\/90怎么简便计算?
由题意得：1\/6=1\/[2（2+1）]、1\/12=1\/[3（3+1）]、1\/20=1\/[4（4+1）]、1\/30=1\/[5（5+1）]、依次可以表达为1\/[n(n+1)]的形式。所以可得：1\/2+1\/6+1\/12+1\/20+1\/30+1\/42+1\/56+1\/72+1\/90 =1\/(1*2)+1\/(2*3)+1\/(3*4)+1\/(4*5)+1\/(5*6)+1\/(6...
1\/2+1\/6+1\/12+1\/20+1\/30+1\/42的简便运算。
1\/2+1\/6+1\/12+1\/20+1\/30+1\/42 =1\/(1x2)+1\/(2x3)+1\/(3x4)+1\/(4x5)+1\/(5x6)+1\/(6x7)=(1 -1\/2) +(1\/2-1\/3)+...+(1\/6-1\/7)=1 -1\/7 =6\/7 异分母分数相加：1、异分母分数相加，先通分，再按同分母分数相加法去计算，最后要化成最简分数。例1：3\/4+5\/7...
