Transcript Make and compare factor lists Step 1

It is sometimes necessary to break a number into groups to solve a
problem….
Mrs. Baldwin wants to give out pencils and
erasers to her 8th period class. She has 12
pencils and 24 erasers. She wants to divide
them up so each person has the same amount
of pencils and erasers. What is the largest
amount of students that Mrs. Baldwin can hand
out pencils and erasers to?
Greatest Common Factor – The greatest of the
common factors of two or more numbers.
Method 1 – Make and compare factor lists
Step 1-List all factors of both numbers
12
1
2
3
24
12
6
4
1
2
3
4
24
12
8
6
Step 2-Find the largest number that both lists have in
common
GCF= 12
Method 2 – Prime factorization with a Venn Diagram
Step 1-Prime factor both numbers
24
12
3
4
2
2
12
3
2
Step 2-Draw a Venn
Diagram and place
factors common to
both numbers in the
middle
4
2 2
2
2
3
2
Step 3-Multiply all
common factors
together to find
GCF
2 x 2 x 3 = 12
GCF=_______________________
Back to the Question!
• Mrs. Baldwin wants to give out pencils
and erasers to her 8th period class.
She has 12 pencils and 24 erasers.
She wants to divide them up so each
person has the same amount of pencils
and erasers. What is the largest amount
of students that Mrs. Baldwin can hand
out pencils and erasers to?
Answer = 12 students
Now it’s your turn…
• Good luck!!!