2x4分之1+4x6分之1+6x8分之1+.+2006x2008分之1
=(1/2-1/4)*1/2+(1/4-1/6)*1/2+(1/6-1/8)*1/2+.+(1/2006-1/2008)*1/2
=[(1/2-1/4)+(1/4-1/6)+(1/6-1/8)+.+(1/2006-1/2008)]*1/2
=(1/2-1/4+1/4-1/6+1/6-1/8+.+1/2006-1/2008)*1/2
=(1/2-1/2008)*1/2
=1003/2008*1/2
=1003/4016
小学生数学团