解.原式=(2005+2011)÷2008+(2006+2010)÷2008+ (2007+2009 )÷2008+2008÷2008 =2+2+2+1 =7 3 ( =
(2005+2006+2007+2008+2009+2010+2011)÷2008=[(2005+2011)+(2006+2010)+(2007+2009)+2008]÷2008=(2008×2+2008×2+2008×2+2008)÷2008=7