Understanding Lowest Common Multiple (LCM)

This video tutorial explains how to find the lowest common multiple (LCM) of three or more numbers. It introduces the concept of LCM as the smallest number that can be evenly divided by the given numbers. The tutorial demonstrates the use of factor trees and prime factorization to calculate the LCM, providing examples with three and four numbers. The process involves identifying prime factors and applying a rule to use each prime number only once if it appears in multiple numbers. The video concludes with examples to reinforce the learning.

What is the Lowest Common Multiple (LCM)?

• The difference between two numbers.

• The sum of two or more numbers.

• The smallest number that two or more numbers divide into evenly.

• The largest number that divides two or more numbers.

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

• Subtraction

• Factor tree

• Addition

• Long division

What is the first step in finding the LCM using a factor tree?

• Add all numbers together

• Divide the numbers by 2

• Break down each number into its prime factors

• Multiply all numbers together

When finding the LCM, how many times should a prime number be used if it appears in multiple numbers?

• As many times as it appears

• Not at all

• Only once

• Twice

What is the LCM of 16, 24, and 32 as calculated in the video?

• 128

• 48

• 64

• 96

In the example with four numbers, which number is not a prime factor of 26?

• 2

• 3

• 5

• 13

What is the LCM of 12, 30, 18, and 26 as calculated in the video?

• 1980

• 1560

• 1230

• 2340

Which of the following is a prime number used in the factorization of 30?

• 4

• 5

• 9

• 6

Which of the following numbers is not used in the factorization of 18?

• 9

• 5

• 3

• 2

What is the final step in calculating the LCM once all prime factors are identified?

• Add all prime factors

• Multiply all prime factors together

• Subtract the smallest prime factor

• Divide by the largest prime factor