Chapter 5.1 McDougal Littell Middle School Math Course 1 Joseph Williams Melvin E. Sine Elementary Objective: Write whole numbers as the product of prime factors.

Vocabulary Divisible – pg a number is divisible by another number if that other number is a factor of the first. Prime Number – pg a whole number greater than 1 whose only factors are 1 and itself. Composite Number – pg a whole number greater than 1 that has factors other than itself and 1.

Vocabulary Prime Factorization – pg a whole number written as the product of prime factors. Factor Tree – pg a diagram used to write the prime factorization of a number.

Finding Factors Which number has more factors, 12 or 14? Finding Factors is easy! Just list out your multiples! 12:1 x 12 2 x 6 3 x 4 4 x 3 Stop when a pair of factors repeats! 14:1 x 14 2 x 7 7 x 2

Finding Factors What are the factors of 8 and 9?

Divisibility Rules for 2, 3, 5, 6, 9, and 10 2 if the number is even 3 if the sum of its digits is divisible by 3 5 if it ends in 5 or 0 A number is divisible by:

Divisibility Rules for 2, 3, 5, 6, 9, and 10 6 if it is even and divisible by 3. 9 if the sum of its digits is divisible by if it ends with 0. A number is divisible by:

Divisibility Test Check if the following numbers are divisible by 2, 3, 5, 6, 9, and ) 1002.) 4563.) ) ) 1401.) 144

Prime or Composite??? How do we tell if a number is prime or composite? a. 51b. 59 Just list the factors!! 1 x 51 3 x 17 1 x is composite. It has more than one factor. 59 is prime. Its factors are one and itself.

Prime or Composite?? Tell whether the number is prime or composite. 1.) 112.) 133.) 144.) 35 Prime! Composite!

Prime Factorization You all know how to multiply. If you can do that Prime Factorization is easy. Just make a factor tree. 180