Prime and Composite Numbers

Prime Number 4757 A Prime Number is a whole number greater than 1 that has exactly two factors, 1 and itself. Which number is prime?

Composite Number 20 Factors: 1, 2, 4, 5, 10, Factors: 1, 5, 11, 55 A composite number is a whole number greater than one that has more than two factors

Prime Factorization Expressing a composite number as a product of prime numbers Rewrite as: Method 1

Method 2: An easy way of keeping track of the factorization is to do upside-down division. It looks like this: The nice thing about this upside-down division is that, when you're done, the prime factorization is the product of all the numbers around the outside. The factors are circled in red above.

Try prime factorization on these composite numbers!!