1-2+3-4+5-6+···-2002+2003
问题描述:
1-2+3-4+5-6+···-2002+2003
答
1-2+3-4+5-6+···-2002+2003
=(1-2)+(3-4)+(5-6)+···+(2001-2002)+2003
= 2003 -1-1-...-1
=2003 - 1001
=1002