Finding LCM and GCF Using Prime Factorization

The video tutorial explains how to find the greatest common factor (GCF) and the least common multiple (LCM) of two numbers using prime factorization and a Venn diagram. It begins with finding the prime factorization of the numbers 30 and 28. Then, it demonstrates how to fill out a Venn diagram with these factors to identify common and unique factors. The GCF is determined by the common factors in the center of the Venn diagram, while the LCM is calculated by multiplying all factors present in the diagram. The tutorial concludes with the GCF of 30 and 28 being 2, and the LCM being 420.

What is the first step in finding the GCF and LCM using prime factorization?

• Multiply the numbers

• Find the prime factorization of the numbers

• Add the numbers

• Draw a Venn diagram

What is the prime factorization of 30?

• 2 * 3 * 5

• 3 * 5 * 7

• 2 * 2 * 7

• 3 * 3 * 5

What is the prime factorization of 28?

• 3 * 5 * 7

• 2 * 2 * 7

• 2 * 3 * 5

• 2 * 3 * 7

What should be done after finding the prime factorization of the numbers?

• Subtract the numbers

• Add the numbers

• Draw and label a Venn diagram

• Multiply the numbers

Which prime factor is common between 30 and 28?

• 2

• 5

• 7

• 3

What is the greatest common factor (GCF) of 30 and 28?

• 2

• 3

• 7

• 5

What is the first step in finding the least common multiple (LCM) using a Venn diagram?

• Draw a Venn diagram

• Add the numbers

• Find the prime factorization of the numbers

• Multiply all numbers in the Venn diagram

What is the second step in finding the LCM using a Venn diagram?

• Find the prime factorization of the numbers

• Add the numbers

• Draw a Venn diagram

• Multiply all numbers in the Venn diagram

What is the final step in finding the LCM using a Venn diagram?

• Divide the numbers

• Subtract the numbers

• Add the numbers

• Multiply all numbers in the Venn diagram

What is the least common multiple (LCM) of 30 and 28?

• 60

• 420

• 210

• 840