2006÷（2007/2008）=2006×2008/2007=（2007-1）×2008/2007=2007×2008/2007-1×2008/2007=2008-2008/2007=2008-（1+1/2007）=2008-1-1/2007=2007-1/2007=2006又2006/2007望采纳~~~