1 / 42

Unit 1; Part 2: Using Factors for Fractions and Solving Problems

Unit 1; Part 2: Using Factors for Fractions and Solving Problems. You need to be able to find the GCF, LCM and solve problems using them. Advanced Homework Answers pp. 222-223. CHECK CHAPTER % FOR LAST YEARS SHOW. THERE WERE CHANGES!!!!.

tarak
Download Presentation

Unit 1; Part 2: Using Factors for Fractions and Solving Problems

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Unit 1; Part 2:Using Factors for Fractions and Solving Problems You need to be able to find the GCF, LCM and solve problems using them.

  2. Advanced Homework Answers pp. 222-223

  3. CHECK CHAPTER % FOR LAST YEARS SHOW. THERE WERE CHANGES!!!!

  4. Unit 1, Lesson 10Advanced – LCM(least common multiple) Assignment – p. 226; #8-18 even (also find GCF) & 28-31.

  5. LCM • Multiples are any number multiplied by 1, 2, 3, etc. • Multiples of 12: 12, 24, 36, 48, 60… • Multiples get bigger where factors get smaller. • Factors of 12: 1, 2, 3, 4, 6, 12

  6. LCM • Least common multiple (LCM) is the smallest common multiple of 2 or more original numbers. • This is used to find the least common denominator. (Oh, boy. Can’t wait to that! Yuck!!!) • So, use LCM to find LCD.

  7. LCM • THE GCF of 2 or more numbers with nothing in common, is always 1. • The LCM of 2 or more numbers with nothing in common is found by simply multiplying them together.

  8. LCM • Find the GCF and LCM of 7 and 25. • There are no common factors, so… • GCF = 1 and • LCM = 7(25) = 175

  9. LCM • The LCM of 2 numbers with common factors is done exactly the same as GCF, using the same ladder as before. • The GCF is the numbers down the left side multiplied together just like before.

  10. LCM • The LCM is all the numbers on the side and across the bottom multiplied together. • Down the side and across the bottom form a big L for LCM.

  11. GCF and LCM 24 60 12 30 6 15 2 5 ) 2 ) 2 ) 3 LCM= 2x2x3x2x5=120 GCF= 2x2x3=12

  12. GCF and LCM 300 18 150 9 50 3 ) 2 ) 3 GCF=2x3=6 LCM=2x3x50x3=900

  13. GCF and LCM 625 30 125 6 ) 5 GCF=5 LCM=5x125x6=3750

  14. GCF and LCM of 3 Numbers • The GCF works the same way with 3 numbers. • You are done when there are no common factors for ALL 3 numbers.

  15. GCF and LCM of 3 Numbers 18 42 60 9 21 30 3 7 10 ) 2 ) 3 GCF=2x3=6

  16. GCF and LCM of 3 Numbers 18 42 60 9 21 30 3 7 10 ) 2 ) 3 Since the bottom numbers have nothing in common, this example works the same as before. LCM=2x3x3x7x10=1260

  17. GCF and LCM of 3 Numbers 56 14 70 28 7 35 4 1 5 ) 2 ) 7 GCF=2x7=14 LCM=14x20=280

  18. GCF and LCM of 3 Numbers • If there are any repeated factors on the bottom, you must do some additional work to find the LCM. • BUT, you first need to figure the GCF, since the common factors must be from all three numbers.

  19. GCF and LCM of 3 Numbers 200 120 180 100 60 90 50 30 45 10 6 15 ) 2 ) 2 ) 5 GCF=2x2x5=20

  20. GCF and LCM of 3 Numbers • After you find the GCF: • Keep dividing by factors that are common to 2 of the 3 numbers. • The 3rd number that can’t be divided is brought down as is. • Keep going until there are no common factors at all. • The LCM is the product of all the numbers (side and bottom).

  21. GCF and LCM of 3 Numbers 200 120 180 100 60 90 50 30 45 10 6 9 5 3 9 5 1 3 ) 2 ) 2 LCM= 2x2x5x2x3x5x1x3 =1800 ) 5 ) 2 ) 3

  22. GCF and LCM of 3 Numbers 12 18 28 6 9 14 3 9 7 1 3 7 ) 2 ) 2 ) 3 GCF=2 LCM=2x2x3x1x3x7=252

  23. GCF and LCM of 3 Numbers 32 80 96 16 40 48 8 20 24 4 10 12 2 5 6 1 5 3 ) 2 ) 2 ) 2 ) 2 ) 2 GCF=24=16 LCM=25x1x5x3=252

  24. GCF and LCM of 3 Numbers • REMEMBER!!!!!! • You may only work with 2 out of 3 numbers on LCM. • GCF MUST be all 3 numbers.

  25. LCM Find the GCF and LCM of 12 and 15.

  26. LCM Find the GCF and LCM of 3 and 15.

  27. LCM Find the GCF and LCM of 60 and 80.

  28. LCM Find the GCF and LCM of 24 and 36.

  29. LCM • Find the GCF and LCM of 2, 3 & 49. • There are no common factors, so… • GCF = 1 and • LCM = 2(3)(49) = 294

  30. LCM Find the GCF and LCM of 2, 6 and 10.

  31. LCM Find the GCF and LCM of 18, 42 & 60.

  32. LCM Be careful when doing 3 numbers! Check the numbers at the bottom. Do they have ANY common factors? (doesn’t have to be in all 3)

  33. LCM If so: • Find the GCF on the side. (The ones that went into all three.) • Write it down now! • Don’t wait until the end.

  34. LCM • Then keep dividing by factors that are common to 2 of the 3 numbers. • The 3rd number that can’t be divided is brought down as is. • Keep going until there are no common factors at all. The LCM is the product of all the numbers (the L on the side and bottom).

  35. LCM Find the GCF and LCM of 4, 10 and 9.

  36. LCM Find the GCF and LCM of 10, 12 & 15.

  37. LCM Find the GCF & LCM of 200, 120 & 180.

  38. End of Slide Show

  39. End of Lesson 7

  40. Advanced Homework Answersp. 226

More Related