Explain how to write a fraction in its simplest form | Maths

Starter quiz

Tick the numbers in the equation that are factors: 4 × 3 = 12
- 4 ✓
- 3 ✓
- 12
Match the words with their meanings.
- Numerator
  
  ⇔
  
  Number on the top of a fraction. ✓
- Denominator
  
  ⇔
  
  Number on the bottom of a fraction. ✓
- Vinculum
  
  ⇔
  
  Fraction bar or line. ✓
If two or more numbers share the same factor, the factor is known as a ______ factor.
- 'common' ✓
Tick the common factors of 12 and 24
- 1 ✓
- 2 ✓
- 3 ✓
- 4 ✓
- 5
Write one common factor of 8 and 24
- '8' ✓
Tick the common multiples of 3 and 4
- 8
- 9
- 12 ✓
- 16
- 24 ✓

Exit quiz

Write down a common factor of 6 and 18
- '6' ✓
Tick the highest common factor of 6 and 24
- 2
- 3
- 6 ✓
- 24
To find the simplest form of a fraction, we:
- divide the numerator and denominator by a common factor.
- divide the numerator and denominator by the highest common factor. ✓
- make the numerator 1
- make the fraction as small as we can.
Tick the fraction that is the simplest form of ${6} \over {12}$
- ${1} \over {12}$
- ${3} \over {4}$
- ${2} \over {6}$
- ${1} \over {2}$ ✓
Tick the fraction that is the simplest form of ${9} \over {12}$
- ${1} \over {12}$
- ${3} \over {4}$ ✓
- ${3} \over {12}$
- ${1} \over {3}$
To find the simplest form of ${7} \over {21}$ , you could divide the numerator and denominator by:
- 3
- 7 ✓
- 3 and then by 4
- 2 and then by 5

Worksheet

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Presentation

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Lesson Details

Key learning points

A fraction in its simplest form is equivalent to the original fraction.
Equivalent fractions have the same value.
To simplify fractions you divide the numerator and denominator by a common factor.

Common misconception

Pupils think that converting a fraction to its simplest form is the same as making the fraction smaller or making the numerator have a value of one.

Ensure pupils realise that the numerator and denominator are both scaled to find a different representation of the same sized fraction. Provide examples of fractions where the simplest form does not have a numerator of one.

Keywords

Equivalent - If two numbers or expressions have the same value, they are said to be equivalent.
Common factor - When we compare lists of factors of two or more numbers, any factors that are the same are common factors.