1. Economists are interested in the problems of factors that affect prices of goods and services and necessary recourses to produce them, as well as sellers' and buyers' behaviour in the market and the relationship between "price system" and "market mechanism"2. Three main approaches to economics are microeconomics, macroeconomics, and development economics.3. Specialized areas of economics are money economics, international economics, labour economics, industrial economics, agricultural economics, growth economics, mathematical economics, etc.4. Economists use economic models to understand economic problems and make correct predictions5. It is not possible to include all the details in a model because real life is complex and a model is an abstraction from real life. 6. A model usually include essential elements and relationships of a particular economic situation7. An economists choose the model that predicts the results of a particular phenomenon more accurately8. It is necessary to collect and study actual data in order to know how accurate a model is