1-2+3-4+5-6+...+2003-2004=
问题描述:
1-2+3-4+5-6+...+2003-2004=
答
1-2+3-4+5-6+...+2003-2004
=(1-2)+(3-4)+(5-6)+...+(2003-2004)
=-1-1-1-...-1
=-1*1002
=-1002