1/4+1/12+1/24+1/40+……+1/19800=?

1/4+1/12+1/24+1/40……+1/19800=? 1/4+1/12+1/24+1/40+……+1/19800=? 4分之1+1/12+1/24+1/40…+1/19800 1/4+1/12+1/24+1/40+1/84+1/112+1/144+1/180 巧算1/4+1/12+1/24+1/40+1/60+1/84+1/112 简算!4分之1+12分之1+24分之1+40分之1+60分之1 4/1+12/1+24/1+40/1+.19800/1 如何巧算1/4+1/12+1/24+1/40+.+1/19800 巧算1/4+1/12+1/24+1/40+1/60+1/84+1/112求详细过程 1/4+1/12+1/24+1/40+1/60+1/84+1/112能不能说清楚些 1.(1/3是三分之一,依此类推)1/3+1/6+1/10+1/15+1/21+1/28+1/36+1/452.3/2-5/6+7/12-9/20+11/30-13/423.(括号不要打,我写只是为了分辨)1+(1/2+1)+(1/1+2+3)+……+（1/1+2+3+……+10）4.1/4+1/12+1/24+1/40+……+1/19800,第二题是假 1/12+1/24+1/40+1/60+1/84+1/112+1/144+1/180 计算：4分之1+12分之1+24分之1+40分之1+60分之1+...+180分之1=? 4分之1+12分之1+24分之1+40分之1+60分之1+...+180分之1=?快 1/4+1/12+1/24+1/40.+1/19800 1+2+3+4……+20+21+23+24……+40的简便算法 1-2/3-1/6-1/12-1/24-1/48-……1/768 有一列数4,6,1,10,12,9,18,24,25,28,48,49,40,96,91,54…………你能看出规律吗