New
New
Year 5

Explain how to identify a prime number or a composite number

I can explain how to identify a prime number or a composite number.

New
New
Year 5

Explain how to identify a prime number or a composite number

I can explain how to identify a prime number or a composite number.

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Lesson details

Key learning points

  1. A prime number has only 2 factors, 1 and itself.
  2. A composite number is a number with more than 2 factors.

Common misconception

Every number has one and itself as a factor, so every number is a prime number.

Ensure pupils explore the different arrangements that numbers can make with tiles in arrays. Point out that the numbers which cannot be arranged in any way except for one row or column are prime numbers.

Keywords

  • Factor - A factor is a whole number which exactly divides another whole number.

  • Prime number - A prime number is a whole number greater than one which has exactly two factors.

  • Composite number - A composite number is a whole number which has more than two factors.

  • Square number - A square number is the result of multiplying an integer (not a fraction) by itself.

Allow pupils to investigate the possible arrays for each number with each other and encourage them to record their findings in a way that can be communicated to others easily.
Teacher tip

Licence

This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

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6 Questions

Q1.
Match the expression to the correct square number.
Correct Answer:2$$^2$$,4

4

Correct Answer:3$$^2$$,9

9

Correct Answer:11$$^2$$,121

121

Correct Answer:8$$^2$$,64

64

Q2.
What square number is represented by this incomplete factor bug?
An image in a quiz
Correct Answer: 100, one hundred, hundred
Q3.
What is the missing factor of 38 from this list? 1, 2, 19
Correct Answer: 38, thirty eight
Q4.
The number 12 has factors.
Correct Answer: 6, six
Q5.
The number 30 has factors.
Correct Answer: 8, eight
Q6.
Tick the numbers which are factors of both 15 and 20
Correct answer: 1
2
Correct answer: 5
10
15

6 Questions

Q1.
Exactly how many factors does a prime number have?
1
Correct answer: 2
4
It depends on the prime number.
Q2.
Match the number to the correct type.
Correct Answer:Prime number,13

13

Correct Answer:Composite number,12

12

Correct Answer:Square number,16

16

Q3.
What is the next prime number after 13?
Correct Answer: 17
Q4.
True or false: 27 is a prime number.
True
Correct answer: False
Q5.
Select the composite numbers.
2
Correct answer: 4
Correct answer: 10
Correct answer: 16
19
Q6.
Select the prime numbers.
1
Correct answer: 3
9
15
Correct answer: 19