1/1*2+1/2*3+1/3*4+1/4*5+------+1/99*100

1/1*2*3+1/2*3*4+1/3*4*5+...+1/99*100*101 1/1*2*3+1/2*3*4+1/3*4*5+.1/99*100*101 (1+1/1*3)*(1+1/2*4)*(1+1/3*5).(1+1/98*100)*(1+1/99*101) (1+1/1+3)*(1+1/2*4)*(1+1/3*5)*.*(1+1/98*100)*(1+1/99*101) 1/1×2+1/2×3+1/3×4+1/4×5+.+1/98×99+1/99×100=? 1/1*2+1/2*3+1/3*4+1/4*5+.1/98*99+1/99*100=? (1-1/2)(1-1/3)(1-1/4).(1-1/99)(1-1/100)等于? (-1*1\2)+(-1\2*1\3)+(-1\3*1\4)+.+(-1\99*1\100) 1/1*2*3*4+1/2*3*4*5+...+1/97*98*99*100=? |1/3-1/2|+|1/4-1/3|+|1/5+1/4|+...+|1/100-1/99|=?有谁能解急 计算/1/3-1/2/+/1/4-1/3/+/1/5-1/4/+省略号+/1/100-1/99/ 简算|3/1-2/1|+|4/1-3/1|+|5/1-4/1|+...+|100/1-99/1|