1. The problem is to understand what a prime factor is. 2. A prime factor is a factor of a number that is a prime number itself. 3. Prime numbers are numbers greater than 1 that have no divisors other than 1 and themselves. 4. To find the prime factors of a number, you break it down into the set of prime numbers that multiply together to give the original number. 5. For example, the prime factors of 12 are 2 and 3 because $12 = 2 \times 2 \times 3$ and both 2 and 3 are prime numbers. 6. Prime factorization is useful in many areas of mathematics including simplifying fractions, finding greatest common divisors, and least common multiples. 7. In summary, prime factors are the building blocks of a number made up only of prime numbers.