Vocabulary:

numbers that evenly divideanother number.Example: The factors of 6 are: 1, 2, 3, and 6

the product of a number multipliedby a whole number.Example: The multiples of 5 are: 5, 10, 15, 20, 25, 30…

it has exactly two factors—1 and itself.Examples: 2, 3, 5, 7, 11, 13…

Greatest Common Factor—The greatest number that can evenly divide two or more numbers.

Least Common Multiple—The lowest number that is a multiple of two or more numbers.

GCF &LCM

Name: Date: Class Pd: 1 2 3 4 5

Ladder Method Steps:1. Write both numbers inside an upside

down division house2. Outside of the “den” write a factor of

both numbers3. Draw another level of the ladder4. Divide the original numbers by that

factor5. Repeat the process with the new

numbers/answers until you can’t divide evenly anymore

6. Multiple the numbers together that are on the left of the “ladder” to find the GCF.

7. Multiply the numbers on the left AND the numbers in the last “rung” of the ladder to find the LCM!

The GCF is on the left!The LCM is ALL of them!

GCF Listing Method Steps:1. Make a list of the factors of each

number2. Circle the factors that the numbers

share3. Select the greatest, shared number!

Let’s Practice it!

Find the GCF of 15 and 30:15: 1, 3, 5, 1530: 1, 2, 3, 5, 6, 10, 15, 30

Find the GCF of 12 and 20:12: 1, 2, 3, 4, 6, 1220: 1, 2, 4, 5, 10, 20

LCM Listing Method Steps:1. Make a list of the multiples of each

number2. Circle the first (least) multiple that the

numbers share

Let’s Practice it!

Find the LCM of 5 and 6:5: 5, 10, 15, 20, 25, 30, 35, 40, 45, 506: 6, 12, 18, 24, 30

Find the LCM of 3 and 9:3: 3, 6, 9, 12, 15, 189: 9, 18, 27…

2 8 32

4 4 16

x 1 4

GCF

7 14 21

x 2 3

LCM

Vocabulary:

numbers that evenly ___________another number.Example: factors of 6: , , , & _ _

the _____________________ of a number multiplied by a _____________ number.Example: The multiples of 5 are: ____, ____, ____, ____, ____…

it has exactly __________ factors—_____ and itself.Examples: ____, ____, ____, ____, ____, ____…

Greatest Common ________________—The greatest number that can evenly divide two or more numbers.

Least Common _____________________—The lowest number that is a multiple of two or more numbers.

GCF &LCM

Name: Date: Class Pd: 1 2 3 4 5

Ladder Method Steps:1. Write both numbers inside an upside

down division house2. Outside of the “den” write a factor of

both numbers3. Draw another level of the ladder4. Divide the original numbers by that

factor5. Repeat the process with the new

numbers/answers until you can’t divide evenly anymore

6. Multiple the numbers together that are on the left of the “ladder” to find the GCF.

7. Multiply the numbers on the left AND the numbers in the last “rung” of the ladder to find the LCM!

The GCF is on the left!The LCM is ALL of them!

GCF Listing Method Steps:1. Make a list of the factors of each

number2. Circle the factors that the numbers

share3. Select the greatest, shared number!

Let’s Practice it!

Find the GCF of 15 and 30: _________

15: ___, ___, ___, ___

30: 1, ___, 3, ___, 6, ___, ___, 30

Find the GCF of 12 and 20: _________

12: ___, 2, ___, ___, ___, 12

20: 1, ___, 4, ___, 10, ___

LCM Listing Method Steps:1. Make a list of the multiples of each

number2. Circle the first (least) multiple that the

numbers shareLet’s Practice it!

Find the LCM of 5 and 6: _________

5: 5, ___, 15, ___, ___, ___, 35, 40, 45

6: ___, 12, ___, 24, ___

Find the LCM of 3 and 9: _________

3: ___, ___, ___, ___, ___, ___

9: ___, ___, ___

8 32

x

GCF

14 21

x

LCM