1+(-2)+3+(-4)+5+…+2009+(-2010)=_.
问题描述:
1+(-2)+3+(-4)+5+…+2009+(-2010)=______.
答
原式=(1-2)+(3-4)+…+(2009-2010)=(-1)×
=-1005.2010 2
故答案是-1005.