Question

Tính:  \(D=1+2-3-4+5+6-7-8+...-1999-2000+2001+2002-2003\)

Answer 1

D = 1 + 2 - 3 - 4 + 5 + 6 - 7 - 8 + ... - 1999 - 2000 + 2001 + 2002 - 2003

D = ( 1 + 2 - 3 - 4 ) + ( 5 + 6 - 7 - 8 ) + ... + ( 1997 + 1998 - 1999 - 2000 ) + 2001 + 2002 - 2003

D = ( -4 ) + ( -4 ) + ... + ( -4 ) + ( 2001 + 2002 - 2003 )

D = ( -4 ) . 500 + 2000

D = -2000 + 2000

D = 0

Answer 2

D = 1 + 2 - 3 - 4 + 5 + 6 - 7 - 8 + ............. - 1999 - 2000 + 2001 + 2002 - 2003

D = ( 1 + 2 - 3 - 4 ) + ( 5 + 6 - 7 - 8 ) + ............ + ( 1997 + 1998 - 1999 - 2000 ) + 2001 + 2002 - 2003

D = ( -4 ) + ( -4 ) + .............. + ( -4 ) + ( 2001 + 2002 - 2003 )

D = ( -4 ) . 500 + 2000 

D = -2000 + 2000

D = 0