§奥数①(简单的类型)(1)2005×20062006-2006×20042004=_____(2)2005.0514+

3个回答

  • (1)2005×20062006-2006×20042004

    =2005×2006×10001-2006×2004×10001

    =2006×10001×(2005-2004)

    =20062006

    (2)2005.0514+2004.0515-2003.0516-2002.0517+2001.0518+2000.0519-1999.0520-1998.0521+……+1521.0998

    = (2005.0514-2003.0516)+(2004.0515-2002.0517)+(2001.0518-1999.0520)+(2000.0519-1998.0521)+……

    =1.9998+1.9998+……

    =(2-0.0002)×242

    =484-0.0484

    =483.9516