Question

Tính nhanh 

 

 

A=2009×2009×20082008-2008×2008×20092009/2008×20072007

Ở toán tuổi thơ 

Answer 1

A = 2019 x 2018 x 1001 x (2019 - 2008 )/2008 x 2007 x 1001 

   = 2019 x 2018 x 1001 / 2008 x 2017 x 1001 = 2019/2017

Answer 2

A  = 2009 x 2008 x 1001 x ( 2008 - 2009 ) / 2008 x 2007 x 1001

     = 2009 x 2008 x 1001 x (-1) / 2008 x 2007 x 1001 = -2009 / 2007