Find one-third or one-quarter of a number | Maths | Quizalize & Oak National Academy

Starter quiz

Match each part to create whole sentences starting with, 'When the whole has been divided into ...'

four equal parts,

⇔

each part is one-quarter. ✓

two equal parts,

⇔

each part is one-half. ✓

three equal parts,

⇔

each part is one-third. ✓
Match the equation to the correct answer.

$\frac{1}{2}$ of 18 =

⇔

9 ✓

$\frac{1}{2}$ of 12 =

⇔

6 ✓

$\frac{1}{2}$ of 16 =

⇔

8 ✓

$\frac{1}{2}$ of 14 =

⇔

7 ✓

$\frac{1}{2}$ of 20 =

⇔

10 ✓
Match the equations that are the same.

$\frac{1}{2}$ of 10 = 5

⇔

5 = $\frac{1}{2}$ of 10 ✓

$\frac{1}{2}$ of 20 = 10

⇔

10 = $\frac{1}{2}$ of 20 ✓

$\frac{1}{2}$ of 14 = 7

⇔

7 = $\frac{1}{2}$ of 14 ✓

$\frac{1}{2}$ of 18 = 9

⇔

9 = $\frac{1}{2}$ of 18 ✓
__________ of the cakes have a cherry.

one-third

one-half ✓

one quarter
Which equations are true for this representation?

$\frac{1}{2}$ of 18 = 9 ✓

9 = $\frac{1}{2}$ of 18 ✓

$\frac{1}{2}$ of 9 = 18

18 = $\frac{1}{2}$ of 9
Aisha has 14 more pages of her book to read. She will read half the pages today. How many pages will she read today? ______ pages.

'7' ✓

Exit quiz

Correctly match the start and the end of the sentences.

To find one-third of a number,

⇔

you divide the whole into 3 equal parts. ✓

To find one-quarter of a number,

⇔

you divide the whole into 4 equal parts. ✓
Which equations represent this model?

$\frac{1}{3}$ of 9 = 3 ✓

$\frac{1}{2}$ of 9 = 3

3 = $\frac{1}{3}$ of 9 ✓
$Look at this model. What is <Math> \frac{1}{4} </Math> of 12? <span class="blank">______</span>$

Look at this model. What is $\frac{1}{4}$ of 12? ______

'3' ✓
What does this model show?

$\frac{1}{3}$ of 20 = 5

$\frac{1}{2}$ of 20 = 5

$\frac{1}{4}$ of 20 = 5 ✓
Which model shows $\frac{1}{3}$ of 12?
True or false. Lucas and Alex have the same amount of money.

True ✓
False

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Lesson Details

Key learning points

To find a third of a number, you divide the whole into 3 equal parts.
To find a quarter of a number, you divide the whole into 4 equal parts.
It is helpful to use a bar model to help you find one-third or one-quarter of a number.

Common misconception

Children may confuse finding a quarter of a number with finding 4 of the objects, or finding a third of a number with finding 3 of the objects.

Use the stem sentence 'the whole has been divided into ___ equal parts' and draw a bar model to represent this before children attempt to find a quarter or a third of a number.

Keywords

Third - 1 of 3 equal parts of a whole.
Quarter - 1 of 4 equal parts of a whole.