Understanding HCF and LCM

Lara and Lorenzo introduce the concepts of highest common factors (HCF) and lowest common multiples (LCM). They explain that a factor is a number that divides another number exactly, while multiples are the results of multiplying a number by integers. The video provides examples of finding HCF and LCM, using numbers like 16, 24, 15, and 25. The process involves listing factors or multiples, identifying common ones, and selecting the highest or lowest. The video concludes with practice examples and encourages viewers to try finding HCF and LCM on their own.

What is a factor of a number?

• A number that is subtracted from another number

• A number that divides another number exactly

• A number that is multiplied by another number

• A number that is added to another number

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Which of the following is a multiple of 3?

• 7

• 9

• 11

• 13

What is the highest common factor (HCF) of 16 and 24?

• 4

• 6

• 8

• 12

How do you find the highest common factor of two numbers?

• Divide the larger number by the smaller one

• Multiply the two numbers together

• List all factors and find the largest common one

• List all multiples and find the smallest common one

What is the lowest common multiple (LCM) of 16 and 24?

• 96

• 64

• 48

• 32

Which step is NOT part of finding the LCM?

• Find common multiples

• Choose the smallest common multiple

• List multiples of each number

• Choose the largest common multiple

What is the HCF of 15 and 25?

• 15

• 3

• 5

• 10

What is the LCM of 15 and 25?

• 60

• 50

• 75

• 100

What is the HCF of 24 and 36?

• 12

• 10

• 8

• 6

What is the LCM of 24 and 36?

• 48

• 60

• 84

• 72