What is GDP?

GDP stands for Gross Domestic Product. it measures the 
total performance and growth rate of a country, which 
includes the exports, imports, investments and expendeture 
of a country.
    simply:
GDP=C+I+G+(X-M): WHERE: C= CONSUMPTION
                         I= GROSS INVESTMENTS
                         G=GOVERNMENT SPENDING
                        (X-M)= (EXPORTS-IMPORTS)