Question

[Vũ Quốc Việt]

1-2-3+4+5-6-7+...+1996+1997-1998-1999+2000+2001

Answer 1

[Đỗ Khang Huy]

[1-2-3+4]+........+[1997-1998-1999+2000]+2001

=0+0+....+0+2001

=2001

Answer 2

[Đinh Minh Châu]

[1-2-3+4]+........+[1997-1998-1999+2000]+2001

=0+0+....+0+2001

=2001