1992/1993+1991/1993+1990/199+…+3/1993+2/1993+1/1993=?
1992/1993+1991/1993+1990/199+…+3/1993+2/1993+1/1993=?
计算:1996+1995-1994-1993+1992+1991-1990-1989+…+4+3-2-1,结果是____
1-2+3-4+5-6.+1991-1992+1993=?
1994-1993+1992+1991-1990+1989+1988-1987+.+5-4+3+2-1=
计算:1993+1992-1991-1990+1989+1988-1987-1986+…+5+4-3-2+1=_____
巧算1/1990*1991+1/1991+1992+1/1992*1993+1/1993
(2+4+6+…+1992+1994)—(1+3+5+…+1991+1993)=?
1993×1993+1992×1992-1993×1992-1992×1991=______.
1-2+3-4+5-6+…+1991-1992+1993=______.
(1992/1993+1993/1994+1/2)*(1992/1993+1993/1994+1994/1995)-(1
计算 1-2+3-4+5-6+...+1991-1992+1993
1+2+3+4-5-6-7-8+...-1989-1990-1991-1992+1993+1994+1995+1996=