Understand the idea.
One whole, different parts
To partition a number, split its objects into smaller parts. No objects are added or taken away. Fourteen counters can be split into ten and four, or seven and seven; both arrangements still have fourteen altogether.
Choose useful parts
Choose parts that help with the task. Tens and ones help you read a number: . Other splits can work too. Join your parts again to check that they make the whole number you started with.
See the method in action.
Find two splits
Show two ways to split 12 into two parts.
Worked solution
- 1
Make a part of ten.
Taking ten of the twelve leaves two in the other part.
- 2
Check that first split.
Joining the two parts brings back all twelve.
- 3
Make and check a different split.
Seven and five also join to make twelve, so this is a second way.
12 = 10 + 2 and 12 = 7 + 5.
Use tens and ones
Split 46 into tens and ones.
Worked solution
- 1
Separate the four tens.
Four bundles of ten account for forty of the objects.
- 2
Keep the six ones as the other part.
Six loose ones remain after the tens are separated.
- 3
Record and check both parts.
Forty and six together restore the original number.
46 = 40 + 6.
Try it yourself.
Check your understanding
Can 8 and 5 be parts of 13?
Show answer & reasoning
Yes.
Yes. Counting on five from eight reaches thirteen, so . The two parts make the required whole.
Keep practising
6 worksheet questions
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 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.
. Accept any different correct split.
For example, 6 and 4. - Do 9 and 4 make 12? Explain.
Count on four from nine: .
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 ↗