Give yourself a simple test. Which one of these four twenty dollar bills is the counterfeit? Can you tell?
The bogus bill is the third from the top in the photograph. These bills are showing up in Reno, Nevada, New York, NY and wherever you can guess. If you don't know what to look for - you should try and learn because you may get stuck with some.
Fake money usually has a rough texture. But here are the characteristics you should also look at:
Learn to identify what to look for. You may be surprised to find one! If you do find one, you should give it to the police or they could accuse YOU of trying to pass it!