Understanding LCM and GCF

This video tutorial from Moomoomath and Science explains how to find the Least Common Multiple (LCM) and Greatest Common Factor (GCF) of two, three, four, and five numbers using a factor tree and a chart. The instructor demonstrates the process step-by-step, emphasizing the importance of organizing prime factors in columns and applying specific rules for LCM and GCF calculations. The method is consistent across different numbers of inputs, and the video concludes with a summary and encouragement to apply the technique to more numbers.

What is the first step in finding the LCM and GCF using the method described in the video?

• List all the numbers

• Find the prime factors

• Add the numbers together

• Divide the numbers by 2

When setting up the chart for two numbers, what should you do if there are multiple prime numbers in a column?

• Add the numbers together

• Skip the column

• Bring down only one number

• Bring down all the numbers

How do you determine the GCF for two numbers using the chart?

• Multiply all numbers in the chart

• Bring down numbers present in all columns

• Add all numbers in the chart

• Bring down the largest number

What is the LCM of the numbers 40, 16, and 4 as calculated in the video?

• 100

• 60

• 80

• 40

For three numbers, what is the rule for bringing down numbers in the chart for the GCF?

• Bring down the largest number

• Bring down numbers present in any column

• Bring down numbers present in at least two columns

• Bring down numbers present in all columns

What is the LCM of the numbers 12, 14, and 22 as calculated in the video?

• 720

• 840

• 600

• 924

When finding the GCF for four numbers, what must be true about the numbers in the columns?

• They must be the same in at least two columns

• They must be the same in all columns

• They must be the smallest numbers

• They must be the largest numbers

What is the LCM of the numbers 6, 12, 18, 24, and 36 as calculated in the video?

• 240

• 180

• 360

• 120

For five numbers, what is the rule for bringing down numbers in the chart for the GCF?

• Bring down numbers present in any column

• Bring down the largest number

• Bring down numbers present in all columns

• Bring down numbers present in at least three columns

What is the final GCF for the five numbers discussed in the video?

• 24

• 18

• 12

• 6