Finding GCF and LCM Using Factor Trees

This video tutorial from Moomoomath and Science explains how to find the Least Common Multiple (LCM) and Greatest Common Factor (GCF) of the numbers 6, 12, and 18 using a factor tree method. The instructor demonstrates how to break down each number into its prime factors, create a chart, and use it to calculate the LCM and GCF. The LCM is found by multiplying the highest power of all prime numbers present, while the GCF is determined by multiplying the common prime factors. The video concludes with a summary of the results: LCM is 36 and GCF is 6.

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

• To divide the numbers

• To simplify the numbers

• To identify prime factors

• To add the numbers

Which of the following are the prime factors of 6?

• 2 and 4

• 3 and 5

• 2 and 3

• 1 and 6

How do you represent the number 12 using a factor tree?

• 1 x 12

• 2 x 2 x 3

• 3 x 4

• 2 x 6

What is the next step after creating a factor tree for each number?

• Add the numbers

• Create a chart with prime factors

• Multiply the numbers

• Divide the numbers

When calculating the LCM, what should you do if multiple numbers appear in one column?

• Ignore the column

• Add all numbers

• Bring down all numbers

• Bring down only one number

What is the LCM of 6, 12, and 18?

• 24

• 18

• 36

• 48

What is the rule for finding the GCF using the chart?

• Look for quadruplets

• Look for single numbers

• Look for triplets

• Look for pairs

Which prime factors are common in all three numbers for the GCF?

• 2 and 3

• 3 and 5

• 2 and 4

• 1 and 6

What is the GCF of 6, 12, and 18?

• 2

• 3

• 6

• 12

What is the final step in calculating the GCF?

• Subtract the numbers

• Add the numbers

• Divide the numbers

• Multiply the common prime factors