The idea, step by step
A whole is a landmark, not a stopping point
If one whole is split into four equal parts, each part is one quarter. Keep counting quarter-sized jumps: one quarter, two quarters, three quarters, four quarters, five quarters.
Four quarters make one whole. The next jump is five quarters, not five fifths. The denominator stays four because the piece size stays the same.
Use complete groups
The denominator tells how many pieces complete one whole. With thirds, every group of three thirds is a whole; with fifths, every group of five fifths is a whole.
Use these landmarks to check a fraction. Seven fifths is greater than five fifths but less than ten fifths, so it lies between one and two.
A common trap
Changing the denominator after reaching one whole.
Instead: The denominator describes the size of each part. It stays unchanged as more of those parts are counted.
See the thinking
Count fifths
Count seven fifth-sized pieces. How many wholes have been passed?
- Five fifths make one whole.
- There are two fifths left after making that whole.
- Seven fifths lies between one whole and two wholes.
Count halves on a walk
Each marked section of a path is km. How far is six sections?
- Two half-kilometre sections make 1 km.
- Six sections form three pairs.
- The total is 3 km.
Check your understanding
What comes after when counting in thirds?
Show answer
Add one more third; six thirds form two wholes.
Your turn
6 questions · 8 marks · Work at your own pace.
Read the questions online
- Count the first seven quarter-sized jumps. Write the final fraction.1 mark
- Complete: .1 mark
- How many whole lengths are eight halves?1 mark
- Does lie between 0 and 1, 1 and 2, or 2 and 3?1 mark
- A student says means 4 wholes. Explain the mistake.2 marks
- A jug receives five pours of litre. Write the total in quarters and as a mixed number.2 marks
Read the worked solutions
Equivalent correct methods earn the corresponding marks. Include units where asked.
- Count the first seven quarter-sized jumps. Write the final fraction.1 mark
Each jump adds one quarter; seven jumps make seven quarters.
- Complete: .1 mark
The numerator increases by one; the denominator stays three.
- How many whole lengths are eight halves?1 mark
Each pair of halves makes one whole; eight halves form four pairs.
4 - Does lie between 0 and 1, 1 and 2, or 2 and 3?1 mark
and ; nine fifths is between them.
Between 1 and 2. - A student says means 4 wholes. Explain the mistake.2 marks
The four equal parts together fill one whole; four wholes would be sixteen quarters.
Four quarters make 1 whole. - A jug receives five pours of litre. Write the total in quarters and as a mixed number.2 marks
Four pours make 1 L, with one quarter-litre pour left.
L, or L.
Curriculum reference & lesson scope
Australian Curriculum v9 and SA Curriculum Mathematics
Equivalence; counting beyond one; mixed numbers; number lines.
Official curriculum source ↗