A reporter interviewed Albert Einstein. At the end of the interview, the reporter asked if he could have Einstein's phone number so he could call if he had further questions.
“Certainly” replied Einstein. He picked up the phone directory and looked up his phone number, then wrote it on a slip of paper and handed it to the reporter.
Dumbfounded, the reporter said, "You are considered to be the smartest man in the world and you can't remember your own phone number?”
Einstein replied, “Why should I memorize something when I know where to find it?”