What are economists really looking at when they say the "economy" is growing or shrinking? We demystify Gross Domestic Product, explaining it as a giant national receipt that tracks everything produced within a country's borders. You'll learn the difference between nominal and real GDP, why imports are subtracted, and how to interpret those confusing "annualized" growth rates you see in headlines. We also explore why a 2% growth rate is healthy for the U.S. but would be a disaster for China, and uncover the major things GDP fails to capture—like unpaid housework and the costly cleanup of environmental disasters.