Least Common Multiple - Lesson 1

Least Common Multiple

https://www.youtube.com/watch?v=MQJnKP-y08I

Least Common Multiple

LCM

First lets define what a multiple is..

Multiple is our key word!

Say we are just doing multples of 4: you can just keep adding 4.

Multiple Choice

What are multiples of 7

• 7, 14, 21, 28, ...

• 7, 14, 22, 24, ...

• 7, 14, 19, 21, ...

• 7, 14, 19, 26, ...

Multiple Choice

What are multiples of 6

• 6, 12, 19, 24, ...

• 6, 13, 18, 23, ...

• 6, 12, 18, 24, ...

• 1, 3, 6, ...

Multiple Choice

Which of these is a multiple of 18?

• 2

• 6

• 35

• 54

Open Ended

What are multiples of 8? (List at least five)

Least Common Multiple

When finding the least common multiple we COMPARE

For ex:

What is the least common multiple (LCM) of 2 and 3?

LCM: 6

6 is the least common multiple because its the lowest number they have in common

Lets do another example

• What is the Least Common Multiple (LCM) of 4 and 10?

• multiples of 4: 4, 8, 12, 16, 20, 24, 28, 32, ...

• multiples of 10: 10, 20, 30, 40, ......

• 
  

  LCM: 20

• its the lowest number they have in common

Multiple Choice

What is the least common multiple of 7 and 8?

(Write out the multiples of 7 and 8 to compare.)

• 7

• 56

• 59

• 15

Multiple Choice

What is the least common multiple of 5 and 8?

• 24

• 16

• 59

• 40

Multiple Choice

What is the least common multiple (LCM) of 3 and 12?

• 12

• 24

• 6

• 15

Fill in the Blank

What does LCM stand for?

Multiple Choice

Challenge question: What is the LCM of 2, 4, and 6?

• 6

• 4

• 12

• 2

When finding the LCM of 2, 4 and 6, write them out!

2: 2, 4, 6, 8, 10, 12, 14, ...

4: 4, 8, 12, 16, 20, 24, ...

6: 6, 12, 18, 24, ...

LCM: 12

Multiple Choice

Find LCM of 5, 4, and 10

• 10

• 20

• 30

• 40