The idea, step by step
One whole, different parts
Partition means split into parts. The whole does not change. You can split 14 counters into 10 and 4, or into 7 and 7.
Move counters between the parts to find another split. Check that you still have 14 altogether.
Choose useful parts
Tens and ones are useful for reading a number. For example, 46 can be split into 40 and 6.
You can use other parts too. Each correct split must join back to make the starting number.
A common trap
Thinking a number has only one possible split.
Instead: There are many ways to split a whole. Each pair must join to make the same total.
See the thinking
Find two splits
Show two ways to split 12 into two parts.
- Put 10 in one part and 2 in the other.
- Check: 10 and 2 make 12.
- A different split is 7 and 5, which also makes 12.
Use tens and ones
Split 46 into tens and ones.
- Four tens make 40.
- The other part is six ones.
- Join 40 and 6 to check 46.
Check your understanding
Can 8 and 5 be parts of 13?
Show answer
Yes.
Eight and five together make thirteen.
Your turn
6 questions · Work at your own pace.
Read the questions online
- Split 17 into 10 and another part.
- Split 32 into tens and ones.
- Write a different split of 10 from 5 and 5.
- Do 9 and 4 make 12? Explain.
- Write two different pairs of parts for 16.
- A box has 25 counters. There are 20 in one bag. How many are outside the bag?
Read the worked solutions
- Split 17 into 10 and another part.
10 + 7 = 17.
10 and 7. - Split 32 into tens and ones.
Three tens are 30 and two ones are 2.
30 and 2. - Write a different split of 10 from 5 and 5.
6 + 4 = 10. Accept any different correct split.
For example, 6 and 4. - Do 9 and 4 make 12? Explain.
Count on four from nine: 10, 11, 12, 13.
No. They make 13. - Write two different pairs of parts for 16.
Both pairs join to make 16.
For example, 10 and 6; 8 and 8. - A box has 25 counters. There are 20 in one bag. How many are outside the bag?
25 can be split into 20 and 5.
5
Curriculum reference & lesson scope
Australian Curriculum v9 and SA Curriculum Mathematics
Year 1 counting, place value and partitioning.
Official curriculum source ↗