1.625*1991+1992*8/3-1992=
1993×1993+1992×1992-1993×1992-1992×1991=______.
1-2+3-4+5-6.+1991-1992+1993=?
1.625*1992+1992*0.375-1992怎么用简便方法计算
1991*1992*1993*1994+1-(1992*1992+1991)*(1992*1992+1991)
1+2+3+4-5-6-7-8+...-1989-1990-1991-1992+1993+1994+1995+1996=
1992*1999-1991*2000
1994-1993+1992+1991-1990+1989+1988-1987+.+5-4+3+2-1=
1992/1993+1991/1993+1990/199+…+3/1993+2/1993+1/1993=?
1-2+3-4+5-6+…+1991-1992+1993=______.
(2+4+6+…+1992+1994)—(1+3+5+…+1991+1993)=?
1994-1993+1992+1991-1990.+5-4+3+2-1=
1+2-3-4+5+6-7-8+9+10-11-12…+1989+1990-1991-1992+1993+1994=__