-Macro-Economics deals not with individual quantities as such, but with the aggregates of these quantities, not with the individual income, not with individual prices but with the price level, not with the individual output but with the national output.

1. Theory of Income and Employment - Macro-economics explains what determines the level of national income and employment, and what causes fluctuations in the level of income, outcome and employment. The analysis of consumption and investment functions are important.

2. Theory of General Price and Inflation - The determination of general level of prices and what causes fluctuations in them is analysed. The study of general price level is significant of account of problems created by inflation and depression which are serious economic problems faced by most of the countries in the world.

3. Theory of Growth and Development - The causes of underdevelopment and poverty in poor countries is studied and strategies to accelerate growth and development are suggested. In developed countries, Growth Theory deals with problems of full utilization of increasing productive capacity and explains how higher rate of growth and stability can be achieved.

4. Macro Theory of Distribution - Macro-economics explains what determines the relative shares from the total national income of the various classes. It deals with the relative shares of rent, wages, interest, and profits in total national income.