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Warm-Up. Factor the following numbers to primes using the ladder method. Express in exponential form: 52 48 150. What am I Learning Today?. GCF. How will I show that I learned it?. Show how prime factorization can be used to find GCF Determine the GCF between two sets of data.
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Warm-Up Factor the following numbers to primes using the ladder method. Express in exponential form: • 52 • 48 • 150
What am I Learning Today? GCF How will I show that I learned it? Show how prime factorization can be used to find GCF Determine the GCF between two sets of data
Vocabulary Common factor: Factors shared by two or more whole numbers. Greatest Common Factor (GCF): The largest number that divides two or more numbers evenly.
How do I find the GCF? Use the list method or the ladder method. How do I use the list method? 1. List all the factor pairs for the two numbers. 2. Circle the largest factor that they share. List the GCF for 28 and 42 Factors of 28: Factors of 42: 1, 2, 4, 7, 14, 28 1, 2, 3, 6, 7, 14, 21, 42 The GCF of 28 and 42 is 14. How do I use the ladder method? • Begin with a factor that divides into each number evenly. Does not have to be prime. • Keep dividing until there are no more common factors. • 3. Find the product of the numbers you divided by (GCF IS ON THE LEFT).
Using the ladder, find the GCF for 40 and 16. 2 40 16 2 • 2 •2= 8 2 20 8 2 10 4 The GCF of 40 and 16 is 8 5 2 Remember: GCF is on the left
Find the Greatest Common Factor Use BOTH the list and ladder method in order to check your answers. Factors of 32: 1, 2, 4, 8, 16, 32 Factors of 24: 1, 2, 3, 4, 6, 8, 12, 24 GCF of 32 and 24 32 24 2 16 12 2 8 6 2 4 3 GCF of 54 and 36 54 36 2 Factors of 54: 1, 2, 3, 6, 9, 18, 27, 54 Factors of 36: 1, 2, 3, 4, 6, 9, 12, 18, 36 27 18 3 9 6 3 3 2 Remember: GCF is on the left
Paired Discussion Turn to a partner and discuss the following: What is the GCF of two prime numbers? Explain. Each prime number only has two factors, so they can ONLY share the number ONE.