Prime Numbers and Prime Factorization of a Number

Factors and Prime Numbers: Defines factors and prime numbers, and how to determine if a number is prime or not.        

http://www.youtube.com/watch?v=vkedo4oAUhA

Prime Factorization of a Number-shows how to write the prime factorization of a number

http://www.youtube.com/watch?v=XpUCTicRBjQ

Greatest Common Factor (GCF) or Divisor of 2 or more numbers