Question

计算1998+1997-1996-1995+1994+1993-1992-1991+……+6+5-4-3+2+1

Answer 1

1998+(1997-1996-1995+1994)+(1993-1992-1991+1990)+……+(5-4-3+2)+1

=1998+0+0+……+0+1

=1999