1+ 3+ 5 +7+ 9 +.+2003+2005+2007+2009+2011

问题描述:

1+ 3+ 5 +7+ 9 +.+2003+2005+2007+2009+2011

(1+2011)+(3+2009)+...+(1005+1007)= 2012×503
= 1012036