GNP (Gross National Product): the market value of all final goods and services produced by the inhabitants of a country in a given period of time (usually one year).
NI (National Income): here the national income is the narrow sense of the national income, refers to a country in a certain period of time (usually one year) for the production of products and the provision of labor services of the various factors of production to obtain the sum of remuneration (income).
Macroeconomic theories include: the theory of national income determination, the theory of the consumption function, the theory of investment, the theory of money, the theory of unemployment and inflation, the theory of economic cycles, the theory of economic growth, and the theory of the open economy.