Math Riddles

Why should you never mention the number 288 in front of anyone?

Because it is too gross (2 x 144 - two gross).  Which weighs more?  A pound of iron or a pound of feathers? Both weigh the same. How is the moon like a dollar? They both have 4 quarters.  It happens once in a minute, twice in a week, and once in a year. What is it? The letter 'e'. How can half of 12 be 7? Cut XII into two halves horizontally. You get VII on the top half.  Credits to: http://www.onlinemathlearning.com/math-riddles.html