Subtracting dates

Hello all,

I am trying to subtract dates from another date - but the formula I have does not work - please help.

=IF((((A3-$B$1)=36)*OR((A3-$B$1)=37)*OR((A3-$B$1)=38)*OR((A3-$B$1)=39)),"Good", "")

Cell D3:D9 is my column with the desired result

Thanks