1/2×1/4+1/4×1/6+1/6×1/8.1/28×1/30=多少?

1,2,4,6, 1/2*2-1+1/4*4-1+1/6*6-1+...+1/50*50-1 |1/4-1/2|+|1/6-1/4|+|1/8-1/6|+```+|1/2008-1/2006| 1/2+1/4+1/6+1/8+.1/n 1/2+1/2+4+1/2+4+6+.+1/2+4+6+...+100 1+1/2+4+1/2+4+6+1/2+4+6+8+.+1/2+4+6+8...+20 2/1+4/1+4/1+6/1+8/1+16/1+32/1=? （1- 1/100)(1- 1/99) .....(1- 1/4)(1- 1/3)(1- 1/2) (-1 1/2)*(-1 1/3)*......(-1 1/6)*(-1 1/7) (1/4+1/2+1/6)×1/24等于什么? 简算：24×(1/2+1/3-1/4-1/6) （1/2+1/3+1/4+1/6）*24 （1/4+2/9-1/6)×36 6/7-1/2+1/4简算 1+2+3/6+1/4= 1+2+4+6@$456 1+1+1+1+1+1+1+1+1+2+5+4+8+3+6+2+1+4等于多少? 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+1+1+1+11+-1-1-1-1-2-3-4-5-6等于