2008×2008分之2009 简便计算RT打错了,是2009分之2008

问题描述:

2008×2008分之2009 简便计算
RT
打错了,是2009分之2008

(2008×2008)/2009=[(2009-1)x2008]/2009=(2009×2008-2008)/2009
=2009×2008/2009-2008/2009=2008-2008/2009=2007又1/2009

2008 ×2008/2009
=2008×(2009-1)/2009
=2008×(2009/2009-1/2009)
=2008×(1 -1/2009)
=2008- 2008/2009
=2007又2009分之1