GDP, GNP, NNP

GDP,GNP,NNP

GDP - Gross Domestic Product
Total market values of goods and services produced by workers and capital within a nation's borders during  1 year.
 Remember the word 'Within NAtional borders'.
that means,

1. ONGC buys some oil-wells in Russia, then whatever ONGC earns from it- is NOT counted here.
2. Your NRI-son sends you money from America - that is also NOT counted.

GNP - Gross National Product
Total market value of goods and services produced by all citizens and capital during a given period (usually 1 yr)

• ONGC's Income from Russia's oil wells is COUNTED!
• + Your NRI-son sends you money from America - that is counted.
• Minus if some American works in India, and sends money back to his family @ US  - then you've to deduct it.

Depreciation:
When you're making some product (mobile phone)
or providing some service (internet, travelbus etc.) 
Then you need to use machines to produce it.
And that machinery has  wear and tear cost. (annual Maintenance, service, repair costs) 
That cost of repair / maintenance of machinery etc. is called Depreciation.

What's the use of Depreciation ?

You'll get income deduction for depreciation.
for Example, Govt. of India provided depreciation of 50% for commercial vehicles purchased on or between January-March 2009

that means suppose you're a businessman with a car worth 10 Lakh rs.  for your business purpose.
so 50% depreciation value of 10 Lakh. = 5 LaKh Rs.
and for that you don't have to pay tax
e.g. if you were in the 30% tax bracket then you don't have to pay
5 LaKh X 30 / 100 = 1.5 Lakh Rs. to Govt. as income tax. <-- you don't have to pay that money.

GDP - Depreciation = NET Domestic Product
GNP- Depreciation = Net National Product (NNP)