(1) They shall add to the aggregate valuation of the real property of every county which they believe to be valued below its true and full market or actual value, or authorized percentage thereof, such percentage in each case as will bring it to its true and full market or actual value or authorized percentage thereof;

(2) They shall deduct from the aggregate valuation of the real property of every county which they believe to be valued above its true and full market or actual value, or authorized percentage thereof, such percentage in each case as will reduce it to its true and full market or actual value or authorized percentage thereof;

(3) They shall add to the aggregate valuation of any class of personal property of any county which they believe to be valued below the true and full market or actual value, or authorized percentage thereof, such percentage, in each case, as will raise it to its true and full market or actual value, or authorized percentage thereof;

(4) They shall take from the aggregate valuation of any class of personal property in any county which they believe to be valued above the true and full market or actual value, or authorized percentage thereof, such percentage as will reduce it to its true and full market or actual value or authorized percentage thereof;

(5) If they believe that the valuation of the real or personal property or any class of personal property of any district, city, town, or township of any county should be raised or reduced without raising or reducing the other real or personal property of the county or without raising or reducing it in the same ratio, they may, in every such case, add to or take from the valuation of the real or personal property or any class of personal property of any one (1) or more of the districts, cities, towns, or townships such percentage as they believe will raise or reduce it to its true and full market or actual value, or authorized percentage thereof; and

(6) Before any percentage shall be added to or deducted from the total assessed valuation of any county, township, district, city, or town in this state by the board, it shall cause a notice to be served upon the county judge of the county, who shall cause notice to be published in some newspaper having a general circulation in the county, at least ten (10) days before the date of the proposed change. The notice shall give the date and place at which the board will sit and shall warn the county judge and all citizens of the county to appear at the time and place and show cause, if any they can, why the proposed change should not be made or the assessments increased or reduced.