Economics is traditionally divided into microeconomics and macroeconomics. Microeconomics studies a wide range of phenomena that play out on a relatively small scale: how individuals decide what quantity of something to buy, how firms (businesses) decide what quantity to produce, how the interaction of demand and supply determines a good’s price, how the price of one good may affect the price of another, how those quantities and prices are affected by government regulations, and so on. Macroeconomics focuses on the big picture, the dynamics of an entire regional or national economy. Key topics include inflation, unemployment, overall economic productivity, and the workings of financial systems.