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Do Now 12/7/10. Take out HW from last night. Text page 185, #12-36 evens; #42-46 evens Copy HW in your planner. Text page 190, #16-36 evens In your journal, explain how you simplify fractions. Then simplify the following variable expression. 12) 1/2, 12/24 14) 7/8, 28/32
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Do Now 12/7/10 • Take out HW from last night. • Text page 185, #12-36 evens; #42-46 evens • Copy HW in your planner. • Text page 190, #16-36 evens • In your journal, explain how you simplify fractions. Then simplify the following variable expression.
12) 1/2, 12/24 14) 7/8, 28/32 16) 4/5, 32/40 18) 14/20, 21/30 20) 8/9 22) 23/36 24) 9/10 26) 13/14 28) a) 40/103 b) 63/103 30) 2mn / 5 32) st / 8 34) 3r / 4 36) 7 / t 42) 9/10, 9/10; yes 44) 3/4, 3/4; yes 46) 5/6, 19/24; no Homework Text page 185, #12-36 evens; #42-46 evens
Objective • SWBAT find the least common multiple of two numbers.
Section 4.4 “Least Common Multiple” A multipleof a number is the product of the number and any other number greater than zero. What are the multiples of 5? Think of counting by fives… 5: 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55 …
Least Common Multiple Find the LCM of 6 and 9. List the multiples of the two numbers and then compare. 6: 6, 12, 18, 24, 30, 36, 42 9: 9, 18, 27, 36, 45, 54 From the list you can see that 18 and 36 are common multiples 6 and 9. Of these 18 is the least common multiple.
Least Common Multiple Find the LCM of 4, 6, and 8. List the multiples of the three numbers and then compare. 4: 4, 8, 12, 16, 20, 24, 28, 32, 36, 40, 44, 48, 52 6: 6, 12, 18, 24, 30, 36, 42, 48, 54, 60 8: 8, 16, 24, 32, 40, 48, 56, 64 From the list you can see that 24 and 48 are common multiples 4,6, and 8. Of these 24 is the least common multiple.
Least Common Multiple Find the LCM of 64 and 72. When the numbers are too large to list the multiples of the two numbers, find the prime factorization of each number. The LCM is the product of the common prime factors and the factors that are not common. Not Common Factors Common Factors 64: 2 · 2 · 2· 2 · 2 · 2 2 · 2 · 2 3 · 3 2 · 2 · 2 72: 2 · 2 · 2· 3 · 3 From the list you can see that 2, 2, and 2 are common prime factors, and the factors that are not common are 2, 2, 2, 3, and 3. The LCM is then 2 · 2 · 2· 2 · 2 · 2· 3 · 3 which is 576.
Least Common Multiple Find the LCM of 180 and 378. When the numbers are too large to list the multiples of the two numbers, find the prime factorization of each number. The LCM is the product of the common prime factors and the factors that are not common. Not Common Factors Common Factors 180: 2 · 2 · 3 · 3 · 5 2 · 3 · 32 · 5 3 · 7 378: 2 · 3 · 3 · 3 · 7 From the list you can see that 2, 3, and 3 are common prime Factors, and the factors that are not common are 2, 3, 5, and 7. The LCM is then 2 · 3 · 3 · 2 · 5 · 3 · 7 which is 3780.
Least Common Multiple Find the LCM of 6, 8, and 20. When you have three or more numbers, the common prime factors may only be shared by two of the numbers. The LCM is the product of the common prime factors and the factors that are not common. Not Common Factors Common Factors 6: 2 · 3 2 · 3 · 5 2 · 2 8: 2 · 2· 2 20: 2 · 2· 5 From the list you can see that 2 and 2 are common prime factors, and the factors that are not common are 2, 3, and 5. The LCM is then 2 · 2 · 2 · 3 · 5 which is 120.
Least Common Multiple Find the LCM of 15, 30, and 50. When you have three or more numbers, the common prime factors may only be shared by two of the numbers.The LCM is the product of the common prime factors and the factors that are not common. Not Common Factors Common Factors 15: 3 · 5 5 2 · 3 · 5 30: 2 · 3· 5 50: 2 · 5· 5 From the list you can see that 2, 3, and 5 are common prime factors, and the factor that is not common is 5. The LCM is then 2 · 3 · 5 · 5 which is 150.
Least Common Multiple Find the LCM of 10ab and 6b. The LCM is the product of the common prime factors and the factors that are not common. Not Common Factors Common Factors 10ab: 2 · 5 · a · b 2 · b 5 · a 3 6b: 2 · 3 ·b From the list you can see that 2 and b are common prime factors, and the factors that are not common are 3, 5, and a. The LCM is then 2 · b · 5 · a · 3 which is 30ab.
Least Common Multiple 5 Find the LCM of 2a³b and 3ab. The LCM is the product of the common prime factors and the factors that are not common. Common Factors Not Common Factors 2a³b :2 · a · a · a · b a · b 2 · a · a 3 · b · b · b · b 5 3ab :3 · a · b · b · b · b · b From the list you can see that a and b are common prime factors, and the factors that are not common are 2, 3, a, a, b, b, b, and b. The LCM is then a · b · 2 · a· a · 3· b · b· b · b which is 6a³b. 5
Homework • Text page 190, #16-36 evens