1/1*2+1/2*3+1/3*4+1/4*5+1/5*6+...1/39*40=?(化简!)
1/1×2+1/2×3+1/3×4+1/4×5+...+1/39×40
(1/2+1/3+1/4+…1/39+1/40)+(2/3+2/4+2/5+…2/39+2/40)+(3/4+3/5+3
39/40-3/5-125=?2/3-1/4-1/5=?2/3+3/4-1?
奥数题6年级1/1*2+1/2*3+1/3*4+1/4*5+1/5*6+...1/39*40
1/1*2+1/2*3+1/3*4+1/4*5+...+1/39*40简便运算
1/1×2+1/2×3+1/3×4+1/4×5+…+1/39×40怎么计算如题
1/1*2+1/2*3+1/3*4+1/4*5+...1/39*40怎么计算?
化简:1/1*2+1/2*3+1/3*4+1/4*5+1/5*6+1/6*7+1/7*8+1/8*9+1/9*10
-1/2,+1/3,-1/4,+1/5,-1/6,.
1×2分之1+2×3分之1+3×4分之1+4×5分之1+...+39×40分之
1/2{1/3[1/4(1/5x-1)-6]+4}=1
1+2-3-4+5+6-7-8+9+10-.+38-39-40+41=?-