I'm posting one puzzle, riddle, math, or statistical problem a day. Try to answer each one and post your answers in the comments section. I'll post the answer the next day. Even if you have the same answer as someone else, feel free to put up your answer, too!
Tuesday, March 15, 2011
One Two Four
Some have one. Some have two. Some have four. None have three.
What are they?
EDIT: Sorry for those who tried to answer this as it was originally written. I've fixed it so that it says none have three.