Economics studies a government's monetary policy and other information using mathematical or statistical calculations (differences). Classical and Keynesian are two completely different economic theories. Each theory takes its own approach to monetary policy, consumer behavior and government spending. There are a few distinctions that separate these two theories. To begin with, classical economic theory was developed in the 1700s, during and after industrialization. Say's law, which is the law of the market, is a principle of classical economics according to which “supply creates its own demand” (classical versus Keynesian). It is supply-driven and also relies on a laissez-faire economic market. As we learned in our previous studies, laissez-faire means free market, not dependent on government. Having little or no government allows individuals to act according to their own interests when it comes to economic decisions. Public spending is not a major element in classical theory. It focuses more on consumer spending and business investment because they are the most important elements of economic growth. Classical economists believe that excess government spending will result in an increase in the public sector and a decrease in the private sector, where wealth is created. This theory mainly focuses on finding long-term solutions to economic problems. Classical economists also take into consideration how new theories and current policies will affect, negatively or positively, the free market environment (differences). In contrast, Keynesian economic theory was introduced in the 1930s, during the Great Depression, by a man named John Maynard Keynes (classical versus Keynesian). It relies on spending and aggregate demand, making this theory demand-driven. These economists believe that aggregate demand is influenced by public and private decisions. Public refers to government and private, individuals and businesses. Aggregate demand sometimes affects output, employment and inflation. When the economy begins to slow down, they rely on the government to rebuild it. Keynesian economists, like classical economists, also believe that the economy is made up of consumer spending, government spending, and business investment. However, Keynesian theory asserts that government spending can improve economic growth in the absence of consumer spending and business investment (differences). According to Keynesian theory, wages and prices are not flexible. A static price will give a horizontal short-run aggregate supply curve (classical and Keynesian economics). The main goal of the government stimulus was to save and create jobs almost immediately..