Define the concept of GDP (Gross Domestic Product) and explain how it is calculated.

GDP is a measure of the total monetary value of all goods and services produced within a country’s borders over a specific period, usually a year or a quarter. It is calculated using three different approaches: the production approach, which sums the value added at each stage of production; the income approach, which sums the total income earned by factors of production (wages, rents, interest, and profits); and the expenditure approach, which sums the total spending on final goods and services (consumption, investment, government spending, and net exports). GDP provides an indication of a country’s economic performance and is widely used as a key indicator of economic health.