The idea, step by step
Same whole, different partitions
The denominator tells how many equal parts make one whole. The numerator counts the chosen parts. Two fractions are equivalent when they cover the same amount of the same whole.
Splitting every part into smaller equal parts changes both counts. For example, each half can be split into three sixths, so one half is three sixths. The shaded length has not grown.
Rename without changing the amount
Multiply the numerator and denominator by the same positive whole number to make smaller pieces. Divide both by the same non-zero common factor when equal pieces can be grouped together.
Check with a strip or number line. Multiplying only the top changes the amount; multiplying only the bottom changes the piece size without changing how many pieces you chose.
A common trap
Changing to by changing only the denominator.
Instead: If each half is split in two, count two quarters for the same half. Change both numerator and denominator.
See the thinking
Make sixths
Rename using sixths.
- Each third splits into two sixths.
- Two thirds contain sixths.
- The whole contains sixths.
Group smaller pieces
A ribbon has 4 of its 12 equal sections coloured. What fraction is coloured in thirds?
- Group the twelve sections into three equal groups of four.
- The four coloured sections fill one of these three groups.
- Dividing both 4 and 12 by 4 gives 1 and 3.
Check your understanding
Is equivalent to ?
Show answer
Yes.
Each fourth splits into two eighths, so three fourths cover six eighths.
Your turn
6 questions · 8 marks · Work at your own pace.
Read the questions online
- Write the fraction shaded in the strip.1 mark
- Fill the missing numerator: .1 mark
- Rename in tenths.1 mark
- Write using halves.1 mark
- Which is equivalent to : or ? Explain.2 marks
- Mia colours of a strip. Leo colours of an equal-length strip. Who colours more? Explain.2 marks
Read the worked solutions
Equivalent correct methods earn the corresponding marks. Include units where asked.
- Write the fraction shaded in the strip.1 mark
There are four equal parts and three are shaded.
- Fill the missing numerator: .1 mark
The denominator is multiplied by 4, so multiply the numerator by 4.
4 - Rename in tenths.1 mark
Multiply both 2 and 5 by 2.
- Write using halves.1 mark
Divide both numerator and denominator by 4.
- Which is equivalent to : or ? Explain.2 marks
Each third is two sixths, so two thirds are four sixths.
- Mia colours of a strip. Leo colours of an equal-length strip. Who colours more? Explain.2 marks
; the wholes have the same length.
They colour equal lengths.
Curriculum reference & lesson scope
Australian Curriculum v9 and SA Curriculum Mathematics
Equivalence; counting beyond one; mixed numbers; number lines.
Official curriculum source ↗