1/1*2+1/2*3+1/3*4...+1/99*100+1/(2011*2012)

1/1*2+1/2*3+1/3*4...+1/99*100+1/(2011*2012) 1/1*2+1/2*3+1/3*4.+1/2011*2012+1/2012*2013 找规律.1/1*2+1/2*3+1/3*4.直到1/99*100 1/1*2+1/2*3+1/3*4.+1/99*100这道题怎么做 -1+2-3+4...-99+100 1/1×2+1/2×3+1/3×4+...+1/2009×2010+1/2010× 1+1+2+3+4.+99 1+1+2+3+4.+99+100等于? 计算：1/1*2+1/2*3+1/3*4.+1/98*99+1/99*100=? 怎么简便 (1)计算1/1*2+1/2*3+1/3+4.+1/99*100 (2)1/1*3+1/3*5+1/5*7.+1/49* 求和：|1/2-1|+|1/3-1/2|+.+|1/99-1/98|+|1/100-1/99| 计算|1/2-1|+|1/3-1/2|+.+|1/99-1/98|+|1/100-1/99| |1/2-1|+|1/3-1/2|+.+|1/99-1/98|+|1/100-1/99|