Question

初一数学题计算(-1*1/2)+(-1/2*1/3)=(-1/3*1/4)+...+(1/2008*1/2009)

Answer 1

(-1*1/2)+(-1/2*1/3)+(-1/3*1/4)+...+(-1/2008*1/2009)

=-[1-1/2+1/2-1/3+1/3-1/4+1/4+……+1/2008-1/2009]

=-[1-1/2009]

=-2008/2009 .