Finding the Greatest Common Factor Using Prime Factorization

The video tutorial covers the concept of the greatest common factor (GCF) and how to determine it using two methods: listing all factors and prime factorization. The instructor begins with an introduction and learning goals, followed by a vocabulary review. The first method involves listing all factors of given numbers to find the GCF, demonstrated with examples. The preferred method, prime factorization, is then explained and illustrated with examples. The video concludes with practice problems and a summary of the learning objectives.

What is the essential question of today's lesson?

• How can I use prime factorization to determine the greatest common factor of two or more numbers?

• What is the difference between prime and composite numbers?

• What is the least common multiple of two numbers?

• How can I add and subtract fractions?

What are factors?

• Numbers that can be multiplied together to get another number

• Numbers that can be divided by other numbers

• Numbers that are always prime

• Numbers that are always even

Tags

CCSS.4.OA.B.4

What is the greatest common factor (GCF)?

• The sum of all factors of a number

• The product of all factors of a number

• The smallest factor that two or more numbers have in common

• The largest factor that two or more numbers have in common

Which of the following is a factor of 20?

• 9

• 3

• 4

• 7

Tags

CCSS.4.OA.B.4

What is the greatest common factor of 20 and 16 using the listing method?

• 4

• 2

• 10

• 8

Why is prime factorization preferred over the listing method?

• It reduces the chance of missing factors

• It is easier to remember

• It is faster

• It is more fun

Tags

CCSS.4.OA.B.4

What is the prime factorization of 20?

• 2 x 2 x 5

• 2 x 5 x 5

• 4 x 5

• 2 x 10

What is the prime factorization of 16?

• 4 x 4

• 2 x 8

• 2 x 2 x 2 x 2

• 1 x 16

What is the greatest common factor of 24 and 30 using prime factorization?

• 12

• 3

• 6

• 2

What should you do if you made a mistake in the practice problems?

• Ignore it

• Go back and figure out where you went wrong

• Ask a friend for the answers

• Skip the question

Tags

CCSS.3.OA.D.9