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Factors and Multiples

Bell Ringer: Page 39 in JBHM binder (DOK 2)

Focus/Introduction: Do you remember the “count-bys” (count by 2–2, 4, 6, 8…; count by 3–3, 6, 9, 12…; 4–4, 8, 12, 16…; 5–5, 10, 15, 20,…) from early elementary school. Who can demonstrate how to count by 6? There is actually a mathematical term to describe these. Does anyone know what the term is? Clue-it is similar to “multiply.” Multiple This lesson will explain more about multiples and their partners “factors.”

Guided Practice: (DOK 1) Divisibility rules can be used to determine factors for a number. It is important for you to learn these rules not only for this lesson, but for future mathematical learning.

What do all numbers have in common that are divisible by___?

We are in the binder notes on pages 88 through 89 on the divisibility rules.

Factors A factor of a number is one of two or more numbers that are multiplied together to get a product.

Examples: What are the factors of 8? 1 x 8 = 8 and 2 x 4 = 8 So 1, 2, 4, and 8 are the factors of 8.

Additional Examples: Find the factors of x 50 2 x 25 5 x 10 So, the factors of 50 are 1, 2, 5, 10, 25, and 50.

Find the factors of x x 50 4 x 25 5 x x 10 So, the factors of 100 are 1, 2, 4, 5, 10, 20, 25, 50, and 100.

Find the factors of x 48 2 x 24 3 x 16 4 x 12 6 x 8 So, the factors of 48 are 1, 2, 3, 4, 6, 8, 12, 16, 24, and 48.

Find the factors of x x 62 4 x 31 So, the factors of 124 are 1, 2, 4, 31, 62, and 124.

Common Factors – numbers that are factors of two or more numbers

Examples: Factors of 4 are 1, 2, and 4. Factors of 8 are 1, 2, 4, and 8. Common Factors of 4 and 8 are 1, 2, and 4.

Additional Examples: What are the common factors of 50 and 100? (1, 2, 5, 10, 25, 50) Why are the common factors of 50 and 100 are the same as the factors of 50? What number is a common factor of every number? (1) We are now on the binder notes page 90.

Independent Work/Activity: (DOK 1) Find all factors and the greatest common factor of the following sets of numbers: 24 _______________________________________ 36 _______________________________________ GCF: ___ Prime Factors: _____________

6 _____________________________________ 14 _____________________________________ GCF: ___ Prime Factors: ____________

12 _____________________________________ 15 _____________________________________ GCF: ___ Prime Factors: ____________

3 _____________________________________ 20 _____________________________________ GCF: ___ Prime Factors: ____________

17 _____________________________________ 51 _____________________________________ GCF: ___ Prime Factors: ____________

78 _____________________________________ 96 _____________________________________ GCF: ___ Prime Factors: ____________

Closure: Objective: NO.1c Identify factors and multiples of whole numbers. (DOK 1)

Homework: Find the factors and greatest common factor of the following: 6 and and 20 4 and 34