Microeconomics vs Macroeconomics

Once we know what economics is we come to its two major but inter-related fields, Microeconomics and Macroeconomics.

Microeconomics

In the most simple words we call it 'economics at an individual level'. After all micro means small and an individual unit is small part of an economy. we study the behavior of a consumer, the resource constraints he faces and how he makes his decision in allocating these resources. we talk about his satisfaction level
which in economics is known as utility. we also study an individual firm or industry and how they allocate resources in an efficient manner. 

Microeconomics is also called price theory. Why?

Interestingly, the whole of microeconomics boils down to price determination. prices are determined in market through forces of supply and demand. Supply comes from production of goods and services. producers face various market structures in the form of Perfect competition, Oligopoly, Monopoly and Monopolistic competition. In all these market structures firms objective is profit maximization. Demand on the other hand comes from consumer behavior. Consumers objective is utility maximization. In short, the whole of microeconomics is summarized in two words 'Price Theory'.

Macroeconomics

In Macroeconomics we study economy as a whole or aggregation. As opposed to microeconomics where we study the production of a single good say bread, here we study the production of all goods together and generally call it Gross Domestic Production (GDP). Instead of studying price of a single product we study aggregate price and call it price level. The changes in price level is known as inflation. The third and most important variable that we study in economics is unemployment. To summerize  macroeconomics, it studies everything at a summed up level.