How to find the Highest Common Factor #7

The video tutorial explains how to find the Highest Common Factor (HCF) of numbers. It introduces the concept of HCF and demonstrates two methods to find it: by listing all factors and using prime factorization. The tutorial provides examples, such as finding the HCF of 20 and 28, and 12 and 18, using both methods. It also covers cases where numbers have repeated prime factors. The video concludes with additional examples for practice, including finding the HCF of 28 and 42, and 132 and 420.

What is the highest common factor of 20 and 28?

• 10

• 2

• 4

• 5

Which number is the highest common factor of 12 and 18?

• 3

• 4

• 9

• 6

What are the prime factors of 12?

• 2, 3, 3

• 3, 3, 2

• 2, 2, 3

• 2, 2, 5

If the prime factors of two numbers include 2, 2, and 3, what is their highest common factor?

• 6

• 8

• 12

• 4

For the numbers 28 and 42, which prime factors are common?

• 2 and 3

• 2 and 5

• 2 and 7

• 3 and 7