1+2-3-4+5+6-7-8+9+10-11-12+……+2005+2006-2007-2008+2009+2010
=1+2+(5+6-3-4)+(9+10-7-8)+……+(2005+2006-2003-2004)+(2009+2010-2007-2008)
=3+4+4+……+4+4(502个4)
=3+502*4
=3+2008
=2011
1+2-3-4+5+6-7-8+9+10-11-12+……+2005+2006-2007-2008+2009+2010
=1+2+(5+6-3-4)+(9+10-7-8)+……+(2005+2006-2003-2004)+(2009+2010-2007-2008)
=3+4+4+……+4+4(502个4)
=3+502*4
=3+2008
=2011