2000+1999-1998-1997+1996+1995-1994-1993+1992+1991
2000+1999-1998-1997+1996+1995-1994-1993+1992+1991
2001-2000-1999+1998+1997-1996+1995-1994-1993+1992+1991-1990+
1991+1992+1993+1994+1995+1996+1997+1998+1999+2000+2001+2002=
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
2003+1991-1992+1993-1994+1995-1996+1997-1998+1999-2000+2001-
2001-2000-1999+1998+1997-1996+1995-1994-1993+1992+1991-1990+
1998+1997+1996+1995+1994+1993+1992+1991=
奥数题1999+1998-1997+1996-1995+1994-1993+1992-1991怎么做
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-