Factors & Multiples

Factors & Multiples

by Sophie Sinclair

- Factors are numbers we multiply to get a       mulitple or product

• Multiples are what we get after multiplying factors together

​Factors of 6

1 x 6 = 6 , so 1 and 6 are factors of 6

2 x 3 = 6, so 2 and 3 are factors of 6​

​Multiples of 6

0 x 6 = 0, so 0 is a multiple of 6

1 x 6 = 6, so 6 is a multiple of 6

2 x 6 = 12, so 12 is a multiple of 6

3 x 6 = 18​, so 18 is a multiple of 6... and so on

​Multiples are the times tables of a number

​Factors are the whole numbers we can multiply together to make a number

​0, 6, 12, 18, 24

​1, 2, 3, 6

Multiple Choice

What are the first five multiples of 11?

• 0, 11, 22, 33, 44

• 11, 22, 33, 44, 55

• 1, 11, 5, 2, 5.5

​Let's watch a little YouTube video...

​Find the factors of 12

​Always start with 1 x 12

​Then go to 2 x 6

​Then 3 x 4

​Then 4 x 3 <--- we already have these numbers so we know we're finished.

Multiple Choice

What are the factors of 32?

• 0, 1, 2, 8

• 1, 2, 4, 8, 16, 32

• 32, 64, 96

Multiple Choice

What are the factors of 40?

• 1, 2, 4, 5, 8

• 1, 2, 4, 5, 8, 10, 20, 40

• 40, 80, 120

​Highest Common Factors

​A common factor is a number that divides exactly into two or more different numbers.

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The highest common factor is the largest common factor of those numbers

Multiple Choice

What is the HCF of 16 and 24?

• 2

• 8

• 16

• 4

​A prime number has no factors apart from one and itself!

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​e.g. 5 is a prime number

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​the only way we can make 5, is by doing 1 x 5

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​There are no other factors of 5...

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​5's only factors are 1 and 5 (itself), therefore it is prime!

​​A prime number has no factors apart from one and itself!

​All prime numbers have

exactly two factors!

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​e.g. 2 = 1 x 2

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​The factors of 2 are 1 and 2

​It has exactly two factors,

therefore, 2 is prime

​One is not a prime number because it only has one factor... itself!

​1 x 1 = 1

​Which of these numbers are prime?

​37, 38, 39, 40, 41

​37 can't be divided by any numbers except 1 and itself... it has exactly two factors

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​38 has four factors:

19 x 2 = 38

​1 x 39 = 38

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​39 has four factors:

​3 x 13 = 39

​1 x 39 = 39

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​40 has eight factors:

1, 2, 4, 5, 8, 10, 20 and 40

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​41 can't be divided by any numbers except 1 and itself... it has exactly two factors

Multiple Choice

Based on what we just learned. Which of the following are prime numbers: 37, 38, 39, 40, 41?

• 38, 39

• 37

• 41, 39

• 41, 37

​Composite numbers are those that have more than two factors!

​Ignoring 2, do you notice anything about all the prime numbers?