1/2.1/4,1/6,1/8,1/10...第n个是 1,3,5,7,9,11...第m个是

1/2.1/3.1/4.1/6怎么样算等于1/8 1/2*4+1/4*6+1/6*8+1/8*10+---+1/198*200 ((1/2)-1)*((1/3)-1)*((1/4)-1)*((1/5)-1)*((1/6)-1)*((1/7)-1)*((1/8)-1)*((1/9)-1)*((1/10)-1) 数学题快（-8）+10+2+（-1）（-6）+3+9+（-4）+（-7）用简便运算（-0.8）+1.2+（-0.7）+（-2.1）+0.8+3.51 1+（-1/2)+1/3+(-1/6) 1/2+(-2/3)+4/5+(-1/2)-(+1/3)1全部都要用简便计算 1 （-8）+10+2+（-1） 2.（-6）+3+9+（-4 数学题1/4*1/6+1/6*1/8+1/8*1/10+1/10*/12解法的过程 1/2*4+1/4*6+1/6*8+1/8*10+1/10*12.+1/2010*2012 2/1 3/1 4/1 5/1 6/1 8/1 10/1 12/1 15/1 20/1 10,1,8,1,6,2,4,6,2,（）. 1/2+1/4+1/6+1/8+1/10+.+1/32等于多少? 1/2+1/4+1/6+1/8+1/10+1/12等于多少? 1/2+1/4+1/6+1/8+1/10+1/12如何计算?简便运算 1/2+1/4+1/6+1/8+1/10+1/12.1/9900怎么算啊? 7/12×6+5/12×6-1/4×2.1 1/2*4*6+1/4*6*8+1/6*8*10+.+96*98*100 1/2+1/3+1/4+1/5+1/6+1/7+1/8+1/9+1/10等于多少? 1/2*4+1/6*8+.1/2006*2008+1/4*6+1/8*10+.1/2004*2006=? 1/2×4+1/6×8+.1/2006×2008+1/4×6+1/8×10+.+1/2004×2006 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