Finding the Least Common Multiple

This video tutorial explains how to find the least common multiple (LCM), a useful skill for adding or subtracting fractions. It covers basic and advanced strategies, including using prime factorization for larger numbers. The tutorial provides examples and emphasizes the importance of identifying the first number that multiple numbers can divide into evenly.

Why is finding the Least Common Multiple (LCM) important when dealing with fractions?

• It helps in finding a common denominator.

• It simplifies multiplication of fractions.

• It is used to convert fractions to decimals.

• It is necessary for dividing fractions.

What is the LCM of 5 and 2?

• 10

• 20

• 5

• 15

What is the first step in the strategy for finding the LCM?

• Add all numbers together.

• Pick the largest number.

• Pick the smallest number.

• Multiply all numbers together.

Why is 27 not the LCM of 3 and 9?

• Because 27 is not a multiple of 3.

• Because 27 is not a common multiple.

• Because 9 is the smallest number that both 3 and 9 multiply into.

• Because 27 is not a multiple of 9.

What is the LCM of 8 and 12?

• 96

• 36

• 24

• 48

What is the LCM of 8 and 14?

• 112

• 56

• 42

• 28

What is a limitation of the strategy of picking the largest number and checking its multiples?

• It only works for even numbers.

• It can become cumbersome with larger numbers.

• It only works for two numbers.

• It requires prime factorization.

What is the prime factorization of 36?

• 2 x 3 x 6

• 2 x 2 x 3 x 3

• 2 x 2 x 2 x 3

• 3 x 3 x 4

What is the prime factorization of 20?

• 4 x 5

• 2 x 5 x 5

• 2 x 10

• 2 x 2 x 5

What is the prime factorization of 8?

• 2 x 2 x 2

• 2 x 4

• 2 x 2 x 4

• 4 x 2