what is GDP ? how is it calculated ? explain with examples.

Dear Student
Answer to your question is as follows :

Gross Domestic Product (GDP)

The monetary value of all the finished goods and services produced within a country's borders in a specific time period, though GDP is usually calculated on an annual basis. It includes all of private and public consumption, government outlays, investments and exports less imports that occur within a defined territory. 

GDP = C + G + I + NX
"C" is equal to all private consumption, or consumer spending, in a nation's economy
"G" is the sum of government spending
"I" is the sum of all the country's businesses spending on capital
"NX" is the nation's total net exports, calculated as total exports minus total imports. (NX = Exports - Imports)

Regards