HCF, LCM, prime factor tree - St Sampsons High School

HCF, LCM, prime factor tree - St Sampsons High School

Highest Common Factor Lowest Common Multiple using prime factor trees David Weeks www.Mathsmadeeasy.co.uk Permission given to use for non-commercial use Find the HCF of 60 and 72 Find the LCM of 60 and 72 Find the HCF of 48 and 56 Find the LCM of 48 and 56 Alter animation effects as appropriate play as slide show You will learn how to Make a Prime Factor Tree Find the HCF of two numbers Find the LCM of two numbers Highest Common Factor HCF Take two numbers 8

10 2 Whats the biggest number that will go into both? 2 goes into 8 four times 8 2 = 4 2 goes into 10 five times 10 2 = 5 Theres no bigger number than 2 that goes into both So its the biggest FACTOR or the Highest Common Factor Lowest Common Multiple LCM 8 Take two numbers 40 10 If you do the times table for each at what number do they cross 1

2 3 4 5 6 7 8 16 24 32 40 48 56 64 10 20 30 40 50 60 70 80 The first time they cross is at 40 So its the Lowest Common Multiple of these two numbers 8 Finding HCF and LCM using the prime factor tree Did you know? EVERY number

is made from Prime numbers Multiplied together! The first prime number is 2, then 3, then 5, then 7. Its a number that no other number goes into except itself and one Exercise Find the HCF of 60 and 72 Find the LCM of 60 and 72 Prime Factor Tree for 60 60 Write 60 at the top of the page 60 = prime number 2 x 30 30 = prime number 2 x 15 15 = prime number 3 x prime number 5 30

2 15 2 3 5 60 is all the prime numbers 2 x 2 x 3 x 5 multiplied together Prime Factor Tree for 72 72 Write 72 at the top of the page 72 = prime number 2 x 36 36 = prime number 2 x 18 18 = prime number 2 x 9 9 = prime number 3 x prime number 3 36 2

18 2 2 9 3 3 72 is the prime numbers 2 x 2 x 2 x 3 x 3 multiplied together Finding the Highest Common Factor 72 60 2 30 2

x 15 2 3 18 2 2 5 36 2 x 2 3

Look for common factors in both trees Multiply them together = 12 9 3 12 is the biggest number that goes into both 60 and 72 So it is the Highest Common Factor 3 Finding the Lowest Common Multiple 60 2 18 2 15

3 36 2 30 2 72 5 x 72 =360 5 2 x 3 x60 =360 Look for the factors remaining in either tree 2 9

3 Cross multiply with top number in opposite tree 360 is the Lowest Common Multiple of 60 and 72 3 Exercise Find the HCF of 56 and 48 Find the LCM of 56 and 48 Prime Factor Tree for 56 56 Write 56 at the top of the page 56 = prime number 2 x 28 28 = prime number 2 x 14 14 = prime number 2 x prime number 7 28 2

14 2 2 7 56 is all the prime numbers 2 x 2 x 2 x 7 multiplied together Prime Factor Tree for 48 48 Write 48 at the top of the page 48 = prime number 2 x 24 24 = prime number 2 x 12 12 = prime number 2 x 6 6 = prime number 2 x prime number 3 24 2

12 2 2 6 2 3 48 is the prime numbers 2 x 2 x 2 x 2 x 3 multiplied together Finding the Highest Common Factor 48 56 2 28 2 x

14 2 2 12 2 2 7 24 2 x 2 2 Look for common factors in both trees

Multiply them together = 8 6 2 8 is the biggest number that goes into both 56 and 48 So it is the Highest Common Factor 3 Finding the Lowest Common Multiple 56 2 12 2 14 2

24 2 28 2 48 7 x 48 =336 7 2 x 3 x56 =336 Look for the factors remaining in either tree 2 6 2

Cross multiply with top number in opposite tree 336 is the Lowest Common Multiple of 56 and 48 3 You now know how to Make a Prime Factor Tree Find the HCF of two numbers Find the LCM of two numbers

Recently Viewed Presentations

  • ShakeAlert Earthquake Early Warning Progress and Status Doug

    ShakeAlert Earthquake Early Warning Progress and Status Doug

    CEEWS: Cal OES - Planning ProcessCA Code 8587.8: State Implementation Plan by 1/1/2016 "On the road toward a comprehensive earthquake early warning system, we will face some challenges. Fortunately the California Integrated Seismic Network provides us with the foundation for...
  • Folliculogenesis In Vivo FIV ROM ADOLESCENCE TO MENOPAUSE

    Folliculogenesis In Vivo FIV ROM ADOLESCENCE TO MENOPAUSE

    FIV™ for reproductive management - our first launch product, the Ovulona™ will be - inevitably -- preferred over alternatives SINCE IT IMPROVES QUALITY OF PLEASURE Folliculogenesis In Vivo™ Technology FIV is a convergence of: Life Science ) Ovulona™ Physical science...
  • Kalman Filter Example - Center for Automation Research

    Kalman Filter Example - Center for Automation Research

    Actions and Observations . Through Time. Belief(x. t) (using all evidence to date) Belief ' (x. t) (without latest evidence) Elapse Time. Get Measurement
  • Lecture 2 Rule-based expert systems  Introduction, or what

    Lecture 2 Rule-based expert systems Introduction, or what

    Forward chaining is a technique for gathering information and then inferring from it whatever can be inferred. However, in forward chaining, many rules may be executed that have nothing to do with the established goal. Therefore, if our goal is...
  • Module 6 Teaching Expectations and Guidelines for Success

    Module 6 Teaching Expectations and Guidelines for Success

    Module 6 Teaching Expectations and Guidelines for Success Session Objectives Begin communicating and teaching behavior expectations on the first day of school Develop a calendar/schedule for teaching behavior the first two weeks of school Develop a procedure for teaching new...
  • AIRSPACE NAVIGATION hhheeelllppp!! AIRSPACE NAVIGATION HOW WE SHARE

    AIRSPACE NAVIGATION hhheeelllppp!! AIRSPACE NAVIGATION HOW WE SHARE

    AIRSPACE NAVIGATION hhheeelllppp!! HOW WE SHARE THE SKY WITH ALUMINIUM 1ST Paragliding Club of South Africa Types of Airspace CTA Control Area Planes exit / enter flight corridors on approach / departure Sits above the airport's TMA TMA Terminal Control...
  • Christopher Columbus - stthomas.sanford.pvt.k12.me.us

    Christopher Columbus - stthomas.sanford.pvt.k12.me.us

    The voyage The Natives When they got back... 200 years after Columbus died... Christopher Columbus By, Zoct 6, Drewpat87, and game freak 97 His Childhood He first sailed the ocean blue…. The voyage The Natives When they got back... 200...
  • The Endocrine System

    The Endocrine System

    Describe the role of the endocrine glands in maintaining homeostasis. Name and describe the functions of the primary hormones secreted by each of the endocrine glands. Recognize, define, spell, and pronounce terms relating to the pathology and the diagnostic and...