Greatest Common Factor Confidential

Warm-Up! 5 2.5 152 x 100 Is 171 divisible by 3? How do you know? 5 2.5 152 x 100 Is 171 divisible by 3? How do you know? What rule tells us if a number is divisible by 6? By 9? Make a factor tree for 60 Confidential

Let’s review! Find the mean of the data set below: 69, 73, 75, 58, 85 What is the median of the data set above? What is the range? Confidential

What is Greatest Common Factor (GCF)? GCF: The largest factor shared between two or more numbers Confidential

Ways to find the GCF Make a list of factors for each of the numbers Use Prime Factorization Confidential

Let’s list the factors! 24 1, 2, 3, 4, 6, 8, 12, 24 36 1, 2, 3, 4, 6, 9, 12, 18, 36 Confidential

Which factors do 24 and 36 have in common? 1, 2, 3, 4, 6, 8, 12, 24 36 1, 2, 3, 4, 6, 9, 12, 18, 36 The largest factor they both have in common is 12! GCF: 12 Confidential

Let’s try another example! 9 1, 3, 9 12 1, 2, 3, 4, 6, 12 The greatest common factor is 3 Confidential

You try! Find the GCF by listing the factors: A. 25 15 B. 16 20 Confidential

Find GCF by using prime factorization Step One: Make a factor tree for each number Ex: Confidential

Circle the prime factors in common Step 2 Circle the prime factors in common 54: 2, 3, 3, 3 81: 3, 3, 3, 3 Confidential

Step 3 Multiply the common prime factors Notice that 54 and 81 share three 3’s in common. To get our answer we will multiply 3 x 3 x 3. Our GCF is 27! Confidential

Let’s look at another example! 36: 2, 2, 3, 3 24: 2, 2, 2, 3 36 and 24 share two 2’s and one 3 in common. GCF: 12 Confidential

You try! Find the GCF by using prime factorization 75 50 Confidential

Find the GCF by using Prime Factorization 56 84 Confidential

Break! Confidential

Puzzle http://www.thekidzpage.com/onlinejigsawpuzzles/jigsaw-puzzles/12-piece-jigsaw/clover3805.html Confidential

Word Problems 1a. The Dance Team has 16 dancers dressed in red, 24 dressed in white, and 40 dressed in blue. The head of the team wants to have the same number of dancers in each row. Each row will have dancers with the same color. What is the greatest number of dancers in a row? Confidential

Word Problems 1b. Marie wants to make goodie bags for her birthday party. She wants to put the same number of goodies in each bag. She has 48 candy bars, 80 lollipops, and 32 bottles of bubbles. What’s the largest number of goodie bags she can make? Confidential

Assessment Name two ways to find GCF List the factors to find the GCF 48, 24 27, 39 56, 32, 72 Confidential

3. Find the GCF by using prime factorization a. 90 30 Confidential

Assessment 3b. 144 108 4. If two numbers are prime, what will their GCF be? Confidential

Assessment 5. Use either method to find GCF a. 35, 14, 49 b. 256, 144, 88 Confidential

Today we learned: Greatest Common Factor (GCF) is the largest factor that two or more numbers have in common There are two ways to find GCF: Make a list of factors Use Prime Factorization Confidential