(+1/4)-(+5)+(-1/3)+(负五又三分之二)

3/1：4/1：5/1化简是? 1/3:1/4:1/5化简 (1+1/2+1/3+1/4+1/5)*(1/3+1/4+1)-(1+1/3+1/4)*(1/2+1/3+1/4+1/5) 4、5、1、2、3、4、5 1/3+1/(3+4)+1/(3+4+5)+...+1/(3+4+5+...+20)如何解? /1/3-1/2/+/1/4-1/3/+/1/5-1/4/+.+/1/10-1/9/ |1/3-1/2|+|1/4-1/3|+|1/5-1/4|+.+|1/2008-1/2007| |1/3-1/2|+|1/4-1/3|+|1/5-1/4|+...+|1/10-1/9| (1+1/2+1/3+1/40)*(1/2+1/3+1/4+1/5)-(1+1/2+1/3+1/4+1/5)*(1/2+1/3+1/4)(1+1/2+1/3+1/4)*(1/2+1/3+1/4+1/5)-(1+1/2+1/3+1/4+1/5)*(1/2+1/3+1/4),不好意思,是下面这个! 1+1 2+2 3+3 4+4 5+5 简算：1/1*2+1/2*3+1/3*4+1/4*5+1/5*6 数学题(1/4+1/5+1/6+...+1/671)(1/3+1/4+1/5+..+1/670)-(1/3+1/4+1/5+...+1/671)(1/4+1/(1/4+1/5+1/6+...+1/671)(1/3+1/4+1/5+..+1/670)-(1/3+1/4+1/5+...+1/671)(1/4+1/5+1/6+...+1/670）=? 巧算：(1+1/2+1/3+1/4+1/5)*(1/2+1/3+1/4+1/5+1/6)-(1+1/2+1/3+1/4+1/5+1/6)*(1/2+1/3+1/4+1/5)(1+1/2+1/3+1/4+1/5)*(1/2+1/3+1/4+1/5+1/6)-(1+1/2+1/3+1/4+1/5+1/6)*(1/2+1/3+1/4+1/5)===== 1,2,3,4,5 1,2,3,4,5, 1 2 3 4 5 1,2,3,4,5 化简1/3:4/5