Greatest Common Factor of 3 Numbers

The video tutorial introduces the concept of the greatest common factor (GCF) and demonstrates how to find it for the numbers 42, 126, and 210. The instructor explains the meaning of GCF, breaks down the process of finding factors, and uses a step-by-step approach to determine the GCF. The tutorial emphasizes starting with the smallest number to save time and verifies the solution by checking divisibility.

What is the main topic of the lesson introduced in the video?

• Learning about Prime Numbers

• Understanding the Greatest Common Factor

• Finding the Least Common Multiple

• Exploring Algebraic Expressions

What does the term 'greatest' refer to in the context of GCF?

• The smallest number

• The largest number

• The most common number

• The least common number

Which number is used as the starting point to find its factors?

• 42

• 84

• 210

• 126

Which of the following is a factor of 42?

• 11

• 9

• 6

• 5

What is the first step in finding the GCF of multiple numbers?

• Start with the smallest number

• Start with the largest number

• Divide by 2

• List all numbers

What is the greatest common factor of 42, 126, and 210?

• 7

• 21

• 14

• 42

Why is it efficient to start with the largest factor when checking divisibility?

• It is easier to remember

• It ensures accuracy

• It is a mathematical rule

• It saves time by reducing calculations