Find one million consecutive positive numbers, none of which are prime. Ancient math tells us that prime numbers (2, 3, 5, 7, 11, ...,), which have no factors except for 1 and themselves, go on ...

If you feel a little odd today, your calendar might explain why. Today’s date, 9/11/13, is a mathematical phenomenon so rare that it only occurs five times every 100 years. This is the last time for ...