You’ve all heard the term before, countless times no doubt. But what does it really mean? Well, the biggest clue is in the name. MACROeconomics is a branch of economics that looks at the economy as a whole, specifically, at its structure, performance, and behaviour. It does so by considering aggregate changes to phenomena like gross domestic product (GDP), inflation, price indices, national income and unemployment rates. 

Marginal revenue (MR) measures the change in total revenue that occurs when a firm increases output by one unit, i.e., it is the extra income (or revenue) generated by selling one additional unit.

A market is in equilibrium if at the market price the quantity demanded is equal to the quantity supplied. The price at which the quantity demanded is equal to the quantity supplied is called the equilibrium price or market clearing price and the corresponding quantity is the equilibrium quantity.

Standing in contrast to macroeconomics, microeconomics looks at the choices made by economic actors - be they people, firms, or whole industries -  and how they affect the allocation of scarce resources. Primarily, this involves investigation into why goods and services assume different values and understanding how changing economic conditions can alter the decision-making of economic actors.