Understanding Least Common Multiple (LCM)

This video tutorial explains how to find the least common multiple (LCM) of two or three numbers using a factor tree method. It begins with an introduction to the concept of LCM and demonstrates the process with examples involving two and three numbers. The tutorial highlights the importance of identifying prime factors and avoiding duplicates when calculating the LCM. The video concludes with a practical example using different numbers to reinforce the learning process.

What is the Least Common Multiple (LCM)?

• The difference between two numbers

• The largest number that divides two numbers

• The smallest number that two numbers divide into evenly

• The sum of two numbers

Which method is used in the video to find the LCM?

• Factor tree

• Addition

• Multiplication table

• Long division

What is the LCM of 8 and 42 as calculated in the video?

• 168

• 210

• 126

• 84

When finding the LCM of three numbers, what additional step is necessary?

• Finding duplicates in all three numbers

• Adding all numbers together

• Dividing by the largest number

• Subtracting the smallest number

What is the LCM of 6, 12, and 36 as shown in the video?

• 48

• 36

• 24

• 12

In the example with 5, 20, and 35, which number is identified as a prime factor first?

• 10

• 7

• 5

• 2

What is the LCM of 5, 20, and 35 as calculated in the video?

• 70

• 105

• 140

• 175

Which of the following is NOT a step in finding the LCM using a factor tree?

• Ignoring duplicate factors

• Adding all numbers

• Identifying prime factors

• Multiplying all prime factors

Why is it important to circle prime numbers in a factor tree?

• To separate even numbers from odd numbers

• To mark numbers that are not needed

• To highlight numbers that are used in the LCM calculation

• To identify numbers that can be divided further

What is the purpose of checking off numbers in the factor tree method?

• To ensure all numbers are used

• To avoid using duplicate numbers

• To count the total number of factors

• To simplify the calculation