Exploring Adding and Subtracting Rational Expressions

This video tutorial covers how to find the least common multiple (LCM) and the greatest common factor (GCF) between two numbers. It begins with an introduction to LCM, followed by an example using the numbers 6 and 15. Viewers are then encouraged to practice finding the LCM of 10 and 14. The tutorial transitions to explaining GCF, providing an example with the numbers 21 and 30, and concludes with a practice exercise for finding the GCF of 15 and 35.

What is the first step in finding the least common multiple (LCM) of two numbers?

• Finding the greatest common factor

• Dividing the larger number by the smaller number

• Adding the two numbers

• Listing the multiples of each number

Which of the following is a multiple of 6?

• 5

• 12

• 7

• 9

Tags

CCSS.4.OA.B.4

What is the least common multiple (LCM) of 6 and 15?

• 45

• 15

• 30

• 60

What is the least common multiple (LCM) of 10 and 14?

• 70

• 30

• 20

• 50

What is the first step in finding the greatest common factor (GCF) of two numbers?

• Adding the two numbers

• Listing the factors of each number

• Finding the least common multiple

• Listing the multiples of each number

Which of the following is a factor of 21?

• 5

• 8

• 7

• 9

Tags

CCSS.4.OA.B.4

What are the factors of 30?

• 1, 2, 4, 5, 10, 20

• 1, 2, 3, 5, 6, 10, 15, 30

• 1, 2, 3, 6, 12, 24

• 1, 3, 5, 15, 30

Tags

CCSS.4.OA.B.4

What is the greatest common factor (GCF) of 21 and 30?

• 1

• 3

• 7

• 10

What is the greatest common factor (GCF) of 15 and 35?

• 10

• 7

• 5

• 3

Which of the following statements is true?

• The LCM of two numbers is always smaller than the GCF

• The GCF of two numbers is always larger than the LCM

• The GCF of two numbers is always equal to the LCM

• The LCM of two numbers is always larger than or equal to the GCF