Fallout: New Vegas(Xbox 360)??? How do I hack computer terminals on this game?

Everytime I log on to a computer on this game I cant figure out the right codes to hack it. I only get four tries to pick out of 100 or so words on the screen. Even when it says that the terminal is "easy" I get the same problem. How can I tell which characters on the screen to pick if I only get 4 tries? This is is difficult and it is stopping me from doing a lot of things on this game. 10 points to the first person that helps me.