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Lesson 1 of 10

Explain how to write a fraction in its simplest form

I can explain how to write a fraction in its simplest form

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Lesson 1 of 10
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Explain how to write a fraction in its simplest form

I can explain how to write a fraction in its simplest form

Lesson details

Key learning points

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

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.

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.

Support children by drawing factor bugs and using times tables grids where necessary to help them find the pairs of factors that are common. However, where possible, pupils should be encouraged to use times table knowledge to help them to help them identify common factors.
Teacher tip

Licence

This content is © Oak National Academy Limited (2025), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

Lesson video

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Prior knowledge starter quiz

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6 Questions

Q1.
Tick the numbers in the equation that are factors: 4 × 3 = 12

Correct answer: 4
Correct answer: 3
12

Q2.
Match the words with their meanings.

Correct Answer:Numerator ,Number on the top of a fraction.

Number on the top of a fraction.

Correct Answer:Denominator ,Number on the bottom of a fraction.

Number on the bottom of a fraction.

Correct Answer:Vinculum , Fraction bar or line.

Fraction bar or line.

Q3.
If two or more numbers share the same factor, the factor is known as a factor.

Correct Answer: common

Q4.
Tick the common factors of 12 and 24

Correct answer: 1
Correct answer: 2
Correct answer: 3
Correct answer: 4
5

Q5.
Write one common factor of 8 and 24

Correct Answer: 8, 4, 2, 1

Q6.
Tick the common multiples of 3 and 4

8
9
Correct answer: 12
16
Correct answer: 24

Assessment exit quiz

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6 Questions

Q1.
Write down a common factor of 6 and 18

Correct Answer: 6, 3, 2, 1

Q2.
Tick the highest common factor of 6 and 24

2
3
Correct answer: 6
24

Q3.
To find the simplest form of a fraction, we:

divide the numerator and denominator by a common factor.
Correct answer: divide the numerator and denominator by the highest common factor.
make the numerator 1
make the fraction as small as we can.

Q4.
Tick the fraction that is the simplest form of $${6} \over {12}$$

$${1} \over {12}$$
$${3} \over {4}$$
$${2} \over {6}$$
Correct answer: $${1} \over {2}$$

Q5.
Tick the fraction that is the simplest form of $${9} \over {12}$$

$${1} \over {12}$$
Correct answer: $${3} \over {4}$$
$${3} \over {12}$$
$${1} \over {3}$$

Q6.
To find the simplest form of $${7} \over {21}$$, you could divide the numerator and denominator by:

3
Correct answer: 7
3 and then by 4
2 and then by 5

Lesson appears in

UnitMaths / Addition and subtraction of fractions

Maths

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