Understanding Least Common Multiple (LCM)

This video tutorial explains how to find the least common multiple (LCM) of two numbers using two different techniques: listing multiples and using prime factorization. The video provides step-by-step examples for each method, demonstrating how to find the LCM of pairs of numbers such as 6 and 8, 9 and 12, and 18 and 24. The tutorial highlights the strengths and weaknesses of each technique, helping viewers decide which method they prefer.

What is the Least Common Multiple (LCM) of two numbers?

• The largest number that divides both numbers

• The smallest number that both numbers divide into evenly

• The sum of the two numbers

• The difference between the two numbers

Which of the following is a step in finding the LCM using multiples?

• Writing out the multiples of each number

• Finding the greatest common divisor

• Adding the numbers together

• Subtracting the smaller number from the larger

In the multiples method, what is the LCM of 6 and 8?

• 24

• 12

• 18

• 30

What is the first step in finding the LCM using prime factors?

• Divide the numbers by their greatest common divisor

• Multiply the numbers

• Write out the prime factors of each number

• Add the numbers together

Using prime factors, what is the LCM of 6 and 8?

• 24

• 30

• 18

• 12

What is the LCM of 9 and 12 using the multiples method?

• 18

• 24

• 30

• 36

In the prime factor method, which prime factors are used for 9?

• 3 and 2

• 2 and 2

• 3 and 3

• 2 and 3

What is the LCM of 18 and 24 using the multiples method?

• 48

• 36

• 60

• 72

Which of the following is a prime factor of 18?

• 9

• 7

• 5

• 2

What is a potential drawback of using the prime factor method?

• It only works for even numbers

• It requires a calculator

• It can be time-consuming if not careful

• It requires knowledge of multiplication tables