Question

tính nhanh 

1998 .1998 -1996 .2000

 

Answer 1

=1998.1998-1996.(1998+2)

=1998.1998-1996.1998+1996.2

=1998.(1998-1996)+1996.2

=1998.2+1996.2

=2.(1998+1996)

=2.3994

=7988

Answer 2

1998.1998-1996.2000=4

 

Answer 3

1998x1998-1996x2000=(1996+2)x1998-1996x(1998+2)=1996x1998+2x1998-1996x1998+1996x2=2x1998-1998x2=2x(1998-1996)=2x2=4

Tick nhé Tạ_Thu_Hiền

Answer 4

=    1998 . (1996 + 2 )  - 1996 . (1998 + 2 )

=     1998 . 1996   + 1998 . 2  - 1996 . 1998 + 1996 . 2 

=    ( 1998 . 1996 - 1996 . 1998)  + 2 . (1996 + 1998)

=     0 + 2 . ( 1994 + 2000)

=   2 . 3994

=    7988 

hoac   =  2 . 1994 + 2. 2000

          = 3988 + 4000

             =   7988

tick nha ban , thanks