To determine the total economic cost of building a courthouse, a government leader should multiply the cost of labor by the cost of materials. add the cost of labor and materials. subtract the cost of labor from materials. divide the cost of labor by the cost of materials.

Add the cost of labor to the materials Explanation:

If you multiply you will be getting too much, if you subtract you are saying you aren't paying your workers. if you divide it would make no sense, so your best answer is to add

to provide for the common defense to form a more perfect union to promote the general welfare