Microeconomics considers four categories that a firm's profit could fall in to, assuming that they are following rational decision making. These four categories are economic profit, normal profit, loss minimizing conditions and shutdown. Economic profit is made when a firm's average total cost is less than the price of each addition product at the profit maximizing output. The normal profit is one that occurs when a firm's economic profit is zero. If a firm is in a loss minimizing condition it means that the price is between the average total cost and average variable cost at profit maximizing output. Lastly, a firm may go into shutdown if the price is below average variable cost at the profit maximizing output.
Often examples of microeconomics can be found by contrasting it to the study of macroeconomics. In comparison, macroeconomics considered the sum total of economic activity. This deals with the issues of inflation, unemployment and growth.