巧算1/1990*1991+1/1991+1992+1/1992*1993+1/1993
巧算1/1990*1991+1/1991+1992+1/1992*1993+1/1993
1992/1993+1991/1993+1990/199+…+3/1993+2/1993+1/1993=?
1991*1992*1993*1994+1-(1992*1992+1991)*(1992*1992+1991)
1991*1992*1993*1994+1开平方
计算√(1991*1992*1993*1994+1)-1992^2
1/1900*1991+1/1991*1992+1/1992*1993+.1/2002*2003+1/2003
1/(1/1990+1/1991+1/1992+1/1993+1/1994+1/1995+1/1996+1/1997+1
1994-1993+1992+1991-1990+1989+1988-1987+.+5-4+3+2-1=
计算1996+1995-1994-1993+1992+1991-1990-1989+.-1 结果是
数学问题1989+1991+1993+1995+1997+1999+2001/1990+1992+1994+1996+1
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=?