Question

2002.20 012 001 - 2001 . 20 022 002

Answer 1

2002 x 20012001 = ( 2001 + 1 ) . 20012001 = 2001 x 20012001 + 20012001

2001 x 20022002 = 2001 x ( 20012001 + 10001 ) = 2001 x 20012001 + 2001 x 10001

Ta có   2001 x 20012001 + 20012001 - ( 2001 x 20012001 + 2001 x 10001 ) 

= 2001 x 20012001 + 20012001 - 2001 x 20012001 - 2001 x 10001 

= ( 2001 x 20012001 - 2001 x 20012001 ) + ( 20012001 -  2001 x 10001  )

=  0 + ( 20012001 - 20012001 )

= 0 + 0

= 0