National Income refers to the total monetary value of all goods and services produced within a country over a specific period, usually a year. It serves as a key indicator of a nation's economic performance and overall wealth. National income includes various components such as wages, profits, rents, and taxes, minus subsidies. Calculating national income can be done using different methods, including the production approach, the income approach, and the expenditure approach. Each method provides insights into the economy's health and helps policymakers make informed decisions to promote growth and stability.