2008X2010X(2008X2009分之1+2009X2010分之一)
=2008×2010× 1/(2008×2009)+2008×2010×1/(2009×2010) 约分后得
=2010/2009 + 2008/2009
=4018/2009
=2
2008X2010X(2008X2009分之1+2009X2010分之一)
=2008×2010× 1/(2008×2009)+2008×2010×1/(2009×2010) 约分后得
=2010/2009 + 2008/2009
=4018/2009
=2