-1-2+3+4-5-6+7+8-9-10...-

-1-2+3+4-5-6+7+8-9-10...-2009-2010+2011+2012

2个回答

-1-2+3+4-5-6+7+8-9-10...-2009-2010+2011+2012
=(-1-2+3+4)+(-5-6+7+8)+(-9-10+11+12)+...+(-2009-2010+2011+2012)
=4x2012÷4
=2012