Income approach to measuring GDP is to add up all the income earned by households and firms in the year. Income earned are wages, profits, rents, and interest income. You add up all these and you get the GDP.
GDP = Rent + Interest + Profits + Statistical Adjustments + Wages
Statistical Adjustments are corporate income taxes, dividends, undistributed corporate profits.
Expenditure approach is adding up the market value of all domestic expenditures made on final goods and services in a year. These expenditures are consumption expenditures, investments expenditures, government expenditures, and net exports.
GDP = Personal Consumption Expenditures + Gross Private Fixed Investments + Gov't Expenditures and Investments + (Net Exports - Net Imports)
