What is it?

But, What is a multiple?

It is the product of a whole number multiplied times any other whole number (factors).

7 X 8 = 56 (multiple or product)

REMEMBER: FACTORS AND MULTIPLES ARE DIFFERENT

and What is a Common Multiple?

A Common Multiple is a number that is a multiple of two numbers.

Here are common multiples (products) for the numbers 4 and 10

10 = 10, 20, 30, 40, 50,

4 = 4, 8, 12, 16, 20, 24

How can I find it?

18

2 9

3 3

18: 3x3x2

Method # 1Listing Multiples

Steps:1: Make a List of Multiples2: Circle the common multiples3. Identify the smallest number

Example: Find the LCM of 10 and 12.

10: 10, 20, 30, 40, 50, 60, 70, 80, 90, 100

12: 12, 24, 36, 48, 60

LCM = 60

...

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

10 = 10, 20, 30, 40, 50, 4 = 4, 8, 12, 16, 20, 24

What is the Least Common Multiple of 6 and 8?

8 = 8, 16, 24, 32, 40, 48 6 = 6, 12, 18, 24, 30, 36

What is the Least Common Multiple of 3 and 9

9 = 9, 18, 27, 36, 45, 54 3 = 3, 6, 9, 12, 15, 21,

Steps: 1) Write the prime factorization of each number.(divide it as much as you can!)

3) Then select the rest of the factors and multiply.

2) Select all common factors ONCE.

Method 2: Using Prime Factorization

20

2 10

2 5

18

2 9

3 3

1) Prime factorization:

18: 3x3x220: 2x2x5

2 3 3 53)Multiply all the factors: 2x3x3x5x2: 180

2. Common factors once: 2

Method 2: Prime Factorization

and Select the remaining factors: 3,3,5 and 2

45

5 9

3 3

72

8 9

3 32 4

2 2

PRACTICE: What is the LCM? 360

Practice Exercise 1:

Exercise 2: Find the LCM.

Exercise 3: Find the LCM of the following numbers.