$\dfrac{423134.846267-423133}{846267.423133+423134}$
=$\dfrac{(423133+1).846267-423133}{846267.423133+423134}$
=$\dfrac{423133.846267+846267-423133}{846267.423133+423134}$
=$\dfrac{423133.846267+(846267-423133)}{846267.423133+423134}$
=$\dfrac{423133.846267+423134}{846267.423133+423134}$
=`1`