The county auditor shall add to or deduct from each tract or lot of real property in his county the required percent of the valuation thereof, as it stands after the same has been equalized by the county board of equalization, adding in each case any fractional sum of fifty cents or more, and deducting in each case any fractional sum of less than fifty cents, so that the value of separate tracts or lots contain no fraction of a dollar.
SDCL 10-11-53