# Understand Prime Numbers

In this worksheet, students will be asked to find the difference between prime and composite numbers.

Key stage:  KS 2

Curriculum topic:   Number: Multiplication and Division

Curriculum subtopic:   Know Prime Numbers

Difficulty level:

### QUESTION 1 of 10

In this activity, you will be asked different questions about prime numbers.

Let's recap what prime numbers are.

Prime Numbers

A prime number is a number greater than 1, that can only be divided by itself and 1.

Example:

11 is a prime number, it only has 2 factors, itself and 1.

11 ÷ 11 = 1

11 ÷ 1 = 11

Composite Numbers

Composite numbers are non-prime numbers.

Composite numbers are whole numbers.

Composite numbers can be divided by numbers other than itself and 1.

Composite numbers have more than 2 factors.

For example, 6 is a composite number because it has the factors; 1, 6, 2, 3.

Look carefully at the numbers below.

Select the prime number.

7

26

14

98

Look carefully at the numbers below.

Write the prime number into the box below.

54, 56, 57, 58, 59

Look carefully at the numbers below.

Write the prime number into the box below.

63, 64, 65, 66, 67

Below is a range of numbers, match each number its correct label.

Choose from either 'composite' or 'prime' to label the number.

## Column B

89
Prime
70
Composite
4
Prime
23
Composite

Below is a range of numbers, match each number its correct label.

Choose from either 'composite' or 'prime' to label the number.

## Column B

19
Prime
71
Composite
97
Prime
8
Prime

Can you write all of the prime numbers up to 10?

There are four altogether.

## Column B

19
Prime
71
Composite
97
Prime
8
Prime

Can you write all of the prime numbers between 11 and 19?

There are four altogether.

## Column B

19
Prime
71
Composite
97
Prime
8
Prime

Can you write down the first 5 prime numbers?

## Column B

19
Prime
71
Composite
97
Prime
8
Prime

Look carefully at the numbers given below.

Some are prime and some are composite.

Select only the prime numbers.

 7 39 45 22 23 68 17 11 2 49 Prime Numbers

Look carefully at the numbers given below.

Some are prime and some are composite.

Select only the composite numbers.

 4 19 28 53 18 97 42 73 Prime Numbers
• Question 1

Look carefully at the numbers below.

Select the prime number.

7
EDDIE SAYS
Did you spot it? The prime number here is 7 because it can only be divided equally by itself and 1.
• Question 2

Look carefully at the numbers below.

Write the prime number into the box below.

54, 56, 57, 58, 59

59
EDDIE SAYS
Did you find the prime number? The prime number here is 59 because it is the only number that can only be divided equally by itself and 1.
• Question 3

Look carefully at the numbers below.

Write the prime number into the box below.

63, 64, 65, 66, 67

67
EDDIE SAYS
How did you get on this time? The prime number here is 67 because it is the only number that can only be divided by itself and 1.
• Question 4

Below is a range of numbers, match each number its correct label.

Choose from either 'composite' or 'prime' to label the number.

## Column B

89
Prime
70
Composite
4
Composite
23
Prime
EDDIE SAYS
To correctly label each number you had to consider whether the number had more than 2 factors. 23 and 89 are the prime numbers as they can only be divided by 1, and themselves. 70 and 4 are composite numbers as they have more than 2 factors! You need to know these key terms. Don't worry, by the end of this activity you will.
• Question 5

Below is a range of numbers, match each number its correct label.

Choose from either 'composite' or 'prime' to label the number.

## Column B

19
Prime
71
Prime
97
Prime
8
Composite
EDDIE SAYS
To correctly label each number you had to consider whether the number had more than 2 factors. 19, 71 and 97 are the prime numbers as they can only be divided by 1 and themselves. 8 is the only composite number as it only has 2 factors.
• Question 6

Can you write all of the prime numbers up to 10?

There are four altogether.

EDDIE SAYS
A little challenge in Year 5 is to be able to recall all if the prime numbers up to 19. The primes numbers up to 10 are 2, 3, 5 and 7.
• Question 7

Can you write all of the prime numbers between 11 and 19?

There are four altogether.

EDDIE SAYS
This is the second part of the Year 5 prime number recall challenge! The primes numbers between 11 and 19 are 11, 13, 17 and 19.
• Question 8

Can you write down the first 5 prime numbers?

EDDIE SAYS
The first 5 prime numbers are: 2, 3, 5, 7, 11. It would help to write these down, perhaps you could even make a revision product.
• Question 9

Look carefully at the numbers given below.

Some are prime and some are composite.

Select only the prime numbers.

 7 39 45 22 23 68 17 11 2 49 Prime Numbers
EDDIE SAYS
There were a lot of numbers to consider! The prime numbers are 2, 7, 11, 17, 23.
• Question 10

Look carefully at the numbers given below.

Some are prime and some are composite.

Select only the composite numbers.

 4 19 28 53 18 97 42 73 Prime Numbers
EDDIE SAYS
Again, there were a lot of numbers to consider! The composite numbers are 4, 18, 28, 42. Well done, that’s another activity completed!
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