3rd level; Prime numbers Prime numbers from 1 - 100. Prime numbers are numbers that can only be divided by themselves and one. If a number is a multiple of any other number, then it is not a prime.

Prime numbers are quite extraordinary. They're like "special snowflakes" - unique in the way that they don't have any other positive divisors other than the number 1 and the prime number itself.

This past week, John Pace of Germantown, Tenn., made a massive discovery. He found the largest prime number known to humankind. It's more than 23 million digits long.