“1/2+1/3+2/3+1/4+2/4+3/4+1/5+2/5+3/5+4/5+……+1/10+2/10+3/10+…
求1/2+(1/3+2/3)+(1/4+2/4+3/4)+(1/5+2/5+3/5+4/5)+……+(1/10+2/10
1/2+(1/3+2/3)+(1/4+2/4+3/4)+(1/5+2/5+3/5+4/5)+…+(1/10+2/10+…
(1+2)/1+(2+3)/1+(3+4)/1+(4+5)/1……(9+10)/1
1*3*4+2*6*8+………+n*3n*4n / 1*4*5+2*8*10+………+n*4n*5n
巧算:1×2×3+2×3×4+3×4×5+…+10×11×12
1/2×4+1/3×5+1/4×6+1/5×7+……+1/8×10+1/9×11
计算:1/2×1/3+1/3×1/4+1/4×1/5+…+1/9×1/10
绝对值|1/3-1/2|+|1/4-1/3|+|1/5-1/4|+…+|1/10-1/9|
|3/1-2/1|+|4/1-3/1|+|5/1-4/1|+…+|10/1-9/1|
化简(1*3*4+2*6*8……n*3n*4n)/(1*3*5+2*8*10+……n*4n*5n)
计算:1+1/1+2+1/1+2+3+1/1+2+3+4+…+1/1+2+3+4+5+6+7+8+9+10(过程)
计算:(1-1/2^2)(1-1/3^2)(1-1/4^2)(1-1/5^2)……(1-1/10^2)的值