Find one quarter of 20
Share 20 into 4 equal groups. Each quarter is 5.
The denominator tells how many equal groups to make.
Year 4
Solve problems involving increasingly harder fractions to calculate quantities, and fractions to divide quantities
Find fractions of quantities by sharing into equal parts first and then counting the groups needed.
Lesson overview
Number - fractions
To find a fraction of a quantity, share the whole into the number of equal parts shown by the denominator. Then take the number of parts shown by the numerator.
Find three quarters
If one quarter of 20 is 5, then three quarters is 15.
Use the unit fraction first, then build the non-unit fraction.
Use equal sharing
Fractions of quantities only work when the groups are equal.
Equal sharing is the key step.
Worked example
Find of 30.
- Share 30 into 5 equal groups.
- Each fifth is 6.
- Take 2 of those fifths.
- 6 + 6 = 12, so of 30 is 12.
Round 1: Learn it
Share the quantity equally first, then count the groups named by the fraction.
Finish this round to unlock Round 2: Show you know it.
Question 1
What is of 20?
Question 2
What is of 20?
Question 3
What is of 30?
Question 4
What is of 24?
Question 5
Which statement is true?
Common mistakes
Watch for these as you work through the lesson.
- Taking objects without sharing equally first.
- Mixing up the numerator and denominator.
- Counting the whole quantity again instead of the fraction part.
Related topics
These ideas connect closely to this lesson.
- Count up and down in hundredths; recognise that hundredths arise when dividing an object by one hundred and dividing tenths by ten.
- Add and subtract fractions with the same denominator.