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Do Now 12/1/09. Take out HW from last night. Text page 175, #16-44 multiples of 4; #48-54 evens Copy HW in your planner. Text page 179, #12-46 evens “Pop-Quiz” tomorrow
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Do Now 12/1/09 • Take out HW from last night. • Text page 175, #16-44 multiples of 4; #48-54 evens • Copy HW in your planner. • Text page 179, #12-46 evens • “Pop-Quiz” tomorrow • In your journal, explain what a FACTOR is in your own words. Then give an example of a factor. What do you think the definition of the GREATEST COMMON FACTOR is?
16) 1, 2, 4, 8 20) 1, 2, 3, 4, 6, 9, 12, 18, 36 24) prime 28) composite 32) row 2: 13; row 3: 4, 13; row 4: 2; 2³ · 13 36) 3² · 7 40) 2 · 7 · 11 44) 7 · 31 48) 11 · c · d 50) 3 · f · f · f · f · f · f 52) 5 · x · y · y 54) 2 · y · y · y · y · z · z · z HomeworkText page 175, #16-44 multiples of 4; #48-54 evens
Objective • SWBAT find the greatest common factor of two or more whole numbers
Section 4.2 “Greatest Common Factor” Factor a number that is multiplied in an expression. • Example:2 · 4 = 8 product factor factor Do you know all the factors of 8? 8: 1, 2, 4, 8
Section 4.2 “Greatest Common Factor” LARGEST Find the GCF of 8 and 12. List the factors of the two numbers and then compare. 8: 1, 2, 4, 8 12: 1, 2, 3, 4, 6, 12 From the list you can see that 1, 2, and 4 are common factors. Of these 4 is the greatest common factor.
Greatest Common Factors Find the GCF of 12, 18, and 30. List the factors of the three numbers and then compare. 12: 1, 2, 3, 4, 6, 12 18: 1, 2, 3, 6, 9, 18 30: 1, 2, 3, 5, 6, 10, 15, 30 From the list you can see that 1, 2, 3, and 6 are common factors. Of these 6 is the greatest common factor.
Greatest Common Factors Find the GCF of 180 and 378. When the numbers are too large to list the factors of the two numbers, find the prime factorization of each and then compare. 180: 2 · 2 · 3 · 3 · 5 378: 2 · 3 · 3 · 3 · 7 From the list you can see that 2, 3, and 3 are common prime factors. The greatest common factor of 180 and 378 is the product of 2 · 3 · 3 which is 18.
Greatest Common Factors Find the GCF of 39 and 50. When the numbers are too large to list the factors of the two numbers, find the prime factorization of each and then compare. Relatively Prime: Two numbers are relatively prime if their greatest common factor is 1. 39: 3 · 13 50: 2 · 5 · 5 From the list you can see that there are NO common prime factors. However, two numbers always have 1 as a common factor. So the GCF is 1 and the two numbers are relatively prime.
GCF of Variable Expressions Find the GCF of 12x²y and 6xy³. Write the prime factorization of each and then compare. 12x²y: 2 · 2 · 3 · x · x · y 6xy³: 2 · 3 · x · y · y · y From the list you can see that 2, 3, x, and y are common prime factors. The greatest common factor is the product of 2 · 3 · x · y, which is 6xy.
GCF of Variable Expressions Find the GCF of 18xy² and 28x²y³. Write the prime factorization of each and then compare. 18xy²: 2 · 3 · 3 · x · y · y 28x²y³: 2 · 2 · 7 · x · x · y · y · y From the list you can see that 2, x, y, and y are common prime factors. The greatest common factor is the product of 2 · x · y · y, which is 2xy².
24 Homework • Text page 179, #12-46 evens