Finding GCF and LCM Concepts

The video tutorial explains how to find the least common multiple (LCM) and greatest common factor (GCF) of the numbers 5, 8, and 10 using a factor tree method. It details the process of prime factorization, organizing factors in a chart, and calculating the LCM by multiplying the highest powers of all prime numbers. The GCF is determined by identifying common factors across the numbers. The tutorial concludes with a summary of the results: LCM is 40 and GCF is 1.

What is the purpose of using a factor tree in finding the LCM and GCF?

• To add the numbers together

• To organize the prime factors

• To simplify the numbers

• To divide the numbers

Which of the following is a prime factor of 5?

• 10

• 5

• 3

• 2

How is the number 8 broken down in the factor tree?

• 2 x 2 x 2

• 5 x 2

• 2 x 4

• 4 x 4

What is the LCM of the numbers 5, 8, and 10?

• 50

• 40

• 20

• 30

When finding the LCM, how many times should a repeated prime factor be included?

• As many times as it appears

• Twice

• Three times

• Once

What is the final step in finding the LCM?

• Multiplying all the numbers together

• Subtracting the smallest number

• Dividing by the largest number

• Adding all the numbers

What is the rule for finding the GCF in terms of the number of same numbers in a column?

• Look for one of the same number

• Look for four of the same number

• Look for two of the same number

• Look for three of the same number

What is the GCF of the numbers 5, 8, and 10?

• 1

• 10

• 5

• 2

If no column has three of the same number, what is the GCF?

• 1

• 0

• 2

• 5

What should you do if a column has only two of the same number when finding the GCF?

• Add it

• Multiply it

• Bring it down

• Ignore it