Think of a number!
Double it!
Add 1000!
Half it!
Now take away the number you started with!
You should be left with 500!

I don't know what to say really, make your own minds up. But i will leave you with a couple of riddle's.

An electric train is going north-west, and the wind is comming from the east.
Which way is the smoke blowing?

A plane crashes on the border of France and Germany.
Where do you bury the survivors?