the concept of macroeconomics
the concepts of total spending, total output and total income and the relationship between them
the concept of the five sector circular flow of incomeĀ
the concepts of equilibrium, leakages and injections in the circular flow of income
the effect of changes in leakages and injections on the level of equilibrium in the circular flow of income model
the concept of Gross Domestic Product (GDP)
the expenditure approach to measuring GDP, i.e. GDP = C+I+G+(X-M)