GCSE Secondary Maths Age 13-17 - Number: HCF - Explained

The video tutorial explains how to find the highest common factor (HCF) of the numbers 32, 48, and 72 using factor trees. It breaks down each number into its prime factors and identifies the common factors among them. The tutorial concludes that the HCF is 8 and discusses the importance of method choice, emphasizing that different starting points in factorization lead to the same result.

What is the first step in finding the HCF of numbers using factor trees?

• Divide the numbers by 2

• Add the numbers together

• Break each number into its prime factors

• Multiply the numbers

Which of the following is a prime factor of 48?

• 5

• 9

• 7

• 2

How is the number 72 initially broken down in the factor tree?

• 15 multiplied by 5

• 12 multiplied by 6

• 10 multiplied by 7

• 9 multiplied by 8

What is the highest common factor of 32, 48, and 72?

• 10

• 8

• 4

• 6

Which method could be used as an alternative to factor trees for finding the HCF?

• Trial and error

• Graph plotting

• Subtraction

• Addition