The teacher asked her student to write on the chalkboard the number 55. The student asked, "How do I do that?"
 
Teacher replied, "Write down the number 5, and beside it add another 5."
 
The student wrote one 5 and stopped. The teacher inquired, "What's wrong?"

"I don't know which side to write the other 5?" 

"Hey, man! Please call me a taxi."
 
"You got it! (Pause) Sir, YOU are a taxi!"