• Greatest Common Factor (GCF) - Saxon Publishers

Name
Greatest Common Factor (GCF)
New Calculator Function: gcd(
Example: Find the GCF of 6, 9, and 15.
Demonstration
Graphing Calculator Activity
Step 1 To find the GCF of 6, 9, and 15, first find the GCF of 6 and 9.
Go to the MATH menu by pressing .
TI-83+
TI-73
Press once to go to the NUM
submenu. Select gcd( .
Select gcd( .
Press then .
The screen should display 3.
The GCF of 6 and 9 is .
Step 2 Next find the GCF of 9 and 15.
Return to the MATH menu by pressing .
TI-83+
TI-73
Return to the NUM submenu by pressing once.
Select gcd( .
Select gcd( .
Press then . The
screen should display 3.
The GCF of 9 and 15 is .
Use with Lesson 12, Example 2
4 © Harcourt Achieve Inc. and Stephen Hake. All rights reserved. Saxon Math Intermediate 6
2

Name
Step 3 Now find the GCF of 6 and 15.
Return to the MATH menu by pressing .
TI-83+
TI-73
Practice
Return to the NUM submenu by pressing once.
Select gcd( .
Select gcd( .
Press then .
The screen should display 3.
The GCF of 6 and 15 is .
The GCF of 6, 9, and 15 is .
Use your graphing calculator to answer the following questions.
1. Find the GCF of 13, 26, and 52.
a. The GCF of 13 and 26 is .
b. The GCF of 26 and 52 is .
c. The GCF of 13 and 52 is .
d. The GCF of 13, 26, and 52 is .
Graphing Calculator Activity 2
2. There are 300 students in 6th grade, 350 in 7th grade, and 400 in 8th grade at
a local middle school. The counselors want to group the students so that there
will be an equal number of students from each grade in each homeroom.
a. If the counselors include an equal number of students from each grade in
each homeroom, what is the greatest possible number of homerooms?
(What is the GCF of 300, 350, and 400?)
b. How many students from each grade will be in each homeroom?
6th grade 7th grade 8th grade
c. How many students will be in each homeroom?
Saxon Math Intermediate 6 © Harcourt Achieve Inc. and Stephen Hake. All rights reserved. 5