And you enter the amount of rent you received for the whole year.  So 1,400 x 12.  You enter the total rent you received for the year.  Then you enter your expenses like Mortgage Interest, Property Tax, Insurance, Repairs, etc.  You can only deduct mortgage interest not the principal part of the mortgage.  You should be depreciating the cost of the rental over 27.5 years, that will take care of the principal part of the mortgage.