1+1+1-1-1-1-1+2+3+8+55+99+22-1-1-99-5

(1+1/2)(1-1/2)(1+1/3)(1-1/3).(1+1/99)(1-1/99)简便算法 1+3+5+.+99 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| 1/3+1/5+...1/99=? (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) 99-1+2×3 (1-1/2)(1-1/3)(1-1/4).(1-1/99)(1-1/100)等于? 1-1/2+1/3-1/4+1/5-1/6…+1/99-1/100）/（1/51+1/52+1/53+…+1/99+1/ 1/2*3+1/4*5+1/6*7+...+1/98*99+1/51+1/52+1/53+...1/99