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Year 5

Find the whole when the size of a unit fraction is known

I can find the whole when the size of a unit fraction is known.

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New
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Year 5

Find the whole when the size of a unit fraction is known

I can find the whole when the size of a unit fraction is known.

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Lesson details

Key learning points

  1. The whole has been divided into __ equal parts and this is one of the parts.
  2. There will be __ of these parts in the whole.
  3. The whole is __ times the size of this part.
  4. If you know the size of a unit fraction, you can work out the size of the whole.

Keywords

  • Unit fraction - A unit fraction is a fraction that has a numerator of one.

  • Denominator - The denominator is the number on the bottom of a fraction. It tells us how many parts the whole has been divided into.

Common misconception

When a unit fraction is represented as a quantity greater than one, pupils may think each part of the unit fractions quantity is itself the unit fraction of the whole.

Draw a circle around the quantity each time to encourage pupils to recognise that each set of objects is representative of a quantity that is one part of the whole.


To help you plan your year 5 maths lesson on: Find the whole when the size of a unit fraction is known, download all teaching resources for free and adapt to suit your pupils' needs...

Provide opportunities for pupils to present their thinking practically. It may be useful to use equal-sized shapes (counters/cubes) to allow pupils to recreate the wholes based on the size of the unit fraction.
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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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6 Questions

Q1.
Tick the unit fractions.
Correct answer: $$ \frac{1}{4} $$
$$ \frac{2}{6} $$
$$ \frac{3}{4} $$
Correct answer: $$ \frac{1}{10} $$
Q2.
Tick fractions with a denominator of 4
$$ \frac{4}{5} $$
Correct answer: $$ \frac{3}{4} $$
$$ \frac{4}{8} $$
Correct answer: $$ \frac{1}{4} $$
$$ 4\frac{1}{9} $$
Q3.
Which image shows one-fifth of the whole?
Correct Answer: An image in a quiz
An image in a quiz
Correct Answer: An image in a quiz
An image in a quiz
An image in a quiz
Q4.
What is the value of each part on this number line?
An image in a quiz
$$ \frac{1}{6} $$
$$ \frac{1}{4} $$
Correct answer: $$ \frac{1}{5} $$
$$ \frac{2}{5} $$
Q5.
Calculate $$ \frac{1}{5} $$ × 5 =
Correct Answer: 1, 1 whole
Q6.
Calculate and find the missing value. $$ \frac{1}{9} $$ × = 1
Correct Answer: 9

6 Questions

Q1.
A unit fraction is a fraction with a numerator of
Correct Answer: 1, one
Q2.
If this is the whole, what fraction of the whole is each segment?
An image in a quiz
$$ \frac{1}{4} $$
$$ \frac{2}{5} $$
Correct answer: $$ \frac{1}{5} $$
$$ \frac{5}{1} $$
Q3.
This heart is one-quarter of the whole. How many parts make up the whole?
An image in a quiz
2
3
Correct answer: 4
5
Q4.
If this blue circle is one-eighth of the whole, which images could represent the whole?
An image in a quiz
An image in a quiz
Correct Answer: An image in a quiz
An image in a quiz
Correct Answer: An image in a quiz
An image in a quiz
An image in a quiz
Q5.
These two triangles make up one-fifth of the whole. How many triangles are needed to make the whole?
An image in a quiz
Correct Answer: 10, ten
Q6.
If this 50 p coin is one-tenth of the whole, what is the value of the whole?
An image in a quiz
Correct Answer: £5, 5, 5 pounds