Question

算术:(1998分之1减1)*(1997分之1减1)*(1996分之1减1).(1001分之1减1)*(1000分之1减

Answer 1

(1/1998-1)*(1/1997-1)*(1/1996-1)*...*(1/1001-1)*(1/1000-1)

=(-1997/1998)*(-1996/1997)*(-1995/1996)*...*(-1000/1001)*(-999/1000)

=-(1997/1998)*(1996/1997)*(1995/1996)*...*(1000/1001)*(999/1000)

=-999/1998

=-1/2.