Explain how to identify common factors between two or more numbers | Maths

Starter quiz

Two numbers that multiply each other to form a product are known as:
- multiples
- factors ✓
- products
Tick the number(s) that represent the factors in this equation 21 = 7 × 3
- 21
- 7 ✓
- 3 ✓
Match the factor pairs for the product of 20
- 1
  
  ⇔
  
  20 ✓
- 2
  
  ⇔
  
  10 ✓
- 4
  
  ⇔
  
  5 ✓
Write down the incorrect factor of 30 from this factor bug.
- '7' ✓
Tick the prime factors of 12, using the factor circle to help you.
- 1
- 2 ✓
- 3 ✓
- 4
- 12
Which image of a factor circle represents the number 24 as prime factors?

Exit quiz

Tick the factors of 15
- 1 ✓
- 2
- 3 ✓
- 5 ✓
- 15 ✓
Common factors are:
- Factors that are in every number
- Factors that two or more numbers share ✓
- Factors that are found the most in numbers
Tick the common factors of 12 and 15
- 1 ✓
- 2
- 3 ✓
- 5
- 12
Complete the sentence. ______ is a common factor of every number.
- '1' ✓
Use the prime factors to find the factors of 36 Tick each correct factor
- 4 ✓
- 5
- 6 ✓
- 13
- 18 ✓
Tick the common factors of 8 and 28
- 1 ✓
- 2 ✓
- 4 ✓
- 6
- 8

Worksheet

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Lesson Details

Key learning points

A common factor is a factor which is shared by two or more numbers

Common misconception

Pupils may only record a prime factor once in the Venn diagram even though it might be used more than once in the composition of the number.

It is important the clarify that we are finding common prime factors that are used in the composition of two numbers, and this might include a prime factor being used more than once.

Keywords

Factor - A factor is a whole number which exactly divides another whole number.
Common factor - When we compare lists of factors of two or more numbers, any factors that are the same are common factors.
Prime factor - A prime factor is a factor of a number that is a prime number.