Least Common Multiple (LCM)

The video tutorial explains the concept of least common multiples (LCM) and how to find them. It begins with an introduction to multiples using numbers like 3 and 4, then moves on to define LCM and provide examples with numbers such as 3, 4, and 5. The tutorial discusses methods to find LCM, including writing out multiples and using prime factorization, demonstrated with numbers 12 and 80. Finally, it shows how LCM can be applied to compare fractions with different denominators, using 1/3 and 1/4 as examples.

What is a multiple of a number?

• A number that is smaller than the original number

• A number that divides another number without a remainder

• A number obtained by adding a number to itself

• A number obtained by multiplying a number with positive integers

What is the least common multiple of 3 and 4?

• 12

• 6

• 15

• 9

Which of the following is true about the least common multiple?

• It is always the product of two numbers

• It is always the sum of two numbers

• It is the largest number that divides both numbers

• It is the smallest number that is a multiple of both numbers

How do you find the LCM using prime factorization?

• Subtract the prime factors of the smaller number from the larger number

• Multiply the highest power of each prime factor found in either number

• Divide the larger number by the smaller number

• Add the prime factors of both numbers

What is the LCM of 12 and 80 using prime factorization?

• 160

• 240

• 320

• 120

Why is finding the LCM useful when comparing fractions?

• It helps in finding the sum of fractions

• It allows fractions to have a common denominator

• It makes fractions larger

• It simplifies fractions to their lowest terms

What is the common denominator for fractions 1/3 and 1/4 using LCM?

• 10

• 8

• 12

• 6