m-2m-3m+4m-5m-6m+7m.2004m=?
1个回答

m-2m-3m+4m-5m-6m+7m.2004m

=(1-2-3+4-5-6+7-8-9+...2002-2003-2004)m

=(-4-7-10-..-2005)m

=-(4+7+10+..+2005)m

=-(4+2005)*668/2m

=-671006m