Question

（2010/1-1）x(2009/1-1)x(2008/1-1).(1001/1-1)x(1000/1-1)=?

Answer 1

原式=-（1-1/2010）*…*(1-1/1000) (负号抵消)

=-(2009/2010)*(2008/2009)*…*(1000/1001)*(999/1000)

=-999/2010(2009分之999)