Finding HCF and Prime Factorization

The video tutorial explains how to find the Highest Common Factor (HCF) of 100 and 120 using the prime factorization method. It begins by identifying the prime factors of each number, then highlights the common factors. Finally, it calculates the HCF by multiplying these common factors, resulting in an HCF of 20.

What is the first step in finding the HCF of two numbers using the prime factorization method?

• Subtract the smaller number from the larger one

• Add the numbers together

• Find the prime factors of each number

• Multiply the numbers

Which of the following is a prime factor of 100?

• 3

• 7

• 5

• 9

What is the prime factorization of 120?

• 2 x 2 x 2 x 5 x 5

• 2 x 2 x 3 x 3 x 5

• 2 x 2 x 2 x 3 x 5

• 2 x 3 x 5 x 5

Which of the following numbers is a common prime factor of both 100 and 120?

• 11

• 2

• 7

• 3

How do you calculate the HCF once you have the common prime factors?

• Add the common factors

• Multiply the common factors

• Subtract the common factors

• Divide the common factors

What is the HCF of 100 and 120?

• 10

• 15

• 20

• 25