简算 1/2+1/6+1/12+······+1/9900

简算 1/2+1/6+1/12+······+1/9900 1/2+1/6+1/12+·····+1/90怎么算 观察1/2 1/6 1/12 1/20 1/30·····的排列顺序,第60个数是多少?观察1/2 1/6 1/12 1/20 1/30··························的排列顺序,第60个数是多少? 1-1/2+1/6+1/12+1/20+·········+1/72+1/90巧算 急·····················1+2+3+...+999=? 变态数学题·······方程一道············x+2y+3z=1x=y+12x+3y+5z=2方程组············要过程············我解了之后总觉得无解····· 这几道奥数题谁会,求2014在哪一行那一列 1 2 3 4 5 10 9 8 7 6 11 12 13 14 15 20 19 18 17 16 求2014哪一行那一列 1 2 3 4 5 6 7 8 9 ···· ····· ·························· 1 2 3 4 ·····7 ·······10 ········?1 3 5 7 ·····?······?··········290 1 4 9 ·····?······?··········? 2/1+6/1+12/1+20/1+······+9702/1+9900/1 俗语和名句的填空1······,自知之明.2······,行必果.3工欲善其事,······.4临渊羡鱼,······.5非学无以广才,······.6······,福兮祸之所伏.7项庄舞剑,······.8······,人以群 证明1·3·5·····(2n-1)/2·4·6·····2n 求（2+5+8······+2000）-（1+4+7······+1999）的值.【简算】 1+2+3+4+······+78+79+801/2+1/6+1/12+1/20+······+1/72+1/90100-99+98-97+96-······+4-3+2-11000-1-2-3-4-······-78-79-801/15+2/15+······+13/15+14/15注：例 1/15 就是 十五分之一 1/2+1/6+1/12+······+1/9900埃及分数怎样算 纸鹤数量的意义比如说 1只纸鹤,代表······· 2只纸鹤,代表······· ······················· ···························· ·················· 越多越好, 把自然数从1开始,排列成下表：1 2 4 7 11 16······ 3 5 8 12 17······ 6 9 13 18·····把自然数从1开始,排列成下表：1 2 4 7 11 16······3 5 8 12 17······6 9 13 18······10 14 19······15 20·· 数学题1/2+5/6+1/12+19/20+29/30+41/42+···+89/90简算 正整数按图的规律排列,请写出第二十行,第二十一列的数 列 行 1 2 5 10 17 4 3 61118 9 8 7 12 19 急列 1 2 3 4 5行 1 2 5 10 17······················ 4 3 6 11 18······················9