Introduction
All economic problems arise from scarcity because human wants are unlimited but resources are limited. Economics the science of choice, it is talking about how individuals and societies make a choice from the scarcity. All economic choices can be summarized in three questions: What gets produced? How is it produced? Who gets what is produces? Economists define their work in micro and macro perspective. Microeconomics and Macroeconomics are the two major branches of economics.

What is Microeconomics?
Microeconomics is the study of how households and firms make decisions and how they interact in markets. So all these problems belong to microeconomics: how the consumer reacts when price changes; how the firms decide the output level and how they decide the production method; how should the firms charge their product prices. Microeconomics also considerate the demand and supply of individual goods and services and the equilibrium occurs when the quantity of demands are equal to the quantity of supplies.
A typical example of microeconomics is a mobile phone manufacturer decides to charge what price of their new model of smart phone depends on the demand of the mobile markets. A number of factors would affect the demand of the mobile phone including the price of the product itself, the income of the consumer, the consumer’s amount of accumulated wealth, the price of other competitor’s product, the consumer’s tastes and preferences and the expectations about future income, wealth and prices. The manufacturer also concerns the cost of production of the new model smart phone to decide the price and output level in the market. These decisions include when a consumer (i.e. households) purchases a good and for how much, or how a producer (i.e. firms) determines the price it will charge for its product are the key content of Microeconomics.