Microeconomics: the study of how individuals and how firms make decisions and how they interact in markets. Look at the total income that everyone in the economy is earning (gdp"s job) Gdp: measures total income of everyone in the nation: total expenditure on economy"s output of goods and services. Economy as a whole, the income = expenditures. Every $ spent by a buyer is a $ of income for the seller. Karen pays doug to mow her lawn, this causes gdp to rise by . Gdp: the market value of all final goods and services produced within a country in a given time period. Gdp adds together many different kinds of products into a single measure of the value of economic activity. It uses market prices since market prices reflect the amount people are willing to pay for different goods, this reflects the value of the goods.