Final answer:
The GDP in the United States is estimated to be $21 trillion.
Step-by-step explanation:
The concept of GDP is fairly straightforward: it is just the dollar value of all final goods and services produced in the economy in a year. In the United States, the GDP is estimated to be $21 trillion. This measurement is a full-time job for a brigade of government statisticians, who calculate the GDP and monitor how it changes every few months.