This document provides information on calculating national income using the income method. It discusses three steps: 1) Compensation of employees including salaries, wages, bonuses, and employer contributions to social security. 2) Operating surplus including profit, rent, interest, and dividends. 3) Mixed income of self-employed individuals. It also provides precautions for calculating national income such as excluding transfer incomes, income from secondary goods, and illegal incomes. Factor payments made for factor services are included, while transfer payments without goods/services are excluded.