Final answer:
Gross Domestic Product (GDP) measures the value of all goods and services produced within a country in a year. It is calculated by taking the quantities of all goods and services produced, multiplying them by their prices, and summing the total. GDP can be measured by the sum of what is purchased in the economy or what is produced.
Step-by-step explanation:
Economists generally express the size of a nation's economy as its gross domestic product (GDP), which measures the value of the output of all goods and services produced within the country in a year. GDP is calculated by taking the quantities of all goods and services produced, multiplying them by their prices, and summing the total. Since GDP measures what is bought and sold in the economy, it can be measured either by the sum of what is purchased in the economy or what is produced.