Ta có A = 20112012 - 20112011 = 20112011 . (2011 - 1) = 20112011 . 2010
B= 20112013 - 20112012 = 20112012 . (2011 - 1) = 20112012 . 2010
Vì 20112012 >20112011 nen 20112011 . 2010 < 20112012 . 2010 hay A<B
A=20112012-20112011
A=20112011.(2011-1)
A=20112011.2010
B=20112013-20112012
B=20112012(2011-1)
B=20112012.2010
=)B>A