2006/2007×2008
=2006/2007×(2007+1)
=2006/2007×2007+2006/20007
=2006又2006/2007
2006/2007×2008
=2006/2007×(2007+1)
=2006/2007×2007+2006/2007×1
=2006+2006/2007
=2006又2006/2007
=2008*(1-1/2007)=2008*1-2008*(1/2007)=2008-2008/2007=2006又2006/2007
=2006/2007×(2007+1)
=2006/2007×2007+2006/2007
=2006+2006/2007