1998+1997-1996-1995+1994+1993-1992-1991=?

1998+1997+1996+1995+1994+1993+1992+1991= 2000+1999-1998-1997+1996+1995-1994-1993+1992+1991 1991+1992+1993+1994+1995+1996+1997+1998+1999+2000+2001+2002= 【题目】计算 1998+1997-1996-1995+1994+1993- 1992-1991+…+6+5-4-3+2+ 2001-2000-1999+1998+1997-1996+1995-1994-1993+1992+1991-1990+ 奥数题1999+1998-1997+1996-1995+1994-1993+1992-1991怎么做 1991+1992+1993+1994+1995+1996+1997+1998+1999+2000+2001+2001 试说明1991^1992+1993^1994+1995^1996+1997^1998+1999^2000能被5整除 1999+1998+1997-1996-1995-1994+1993+1992+1991-1990-1989-1988. 找规律计算：1991+1992+1993+1994+1995+1996+1997+1998+1999 1999+1998+1997+1996-1995-1994-1993-1992+1991+1990+1989+1988- 计算:1999+1998+1997-1996-1995-1994+1993+1992+1991-1990-1989-19