AC9M1N02 • Year 1 Maths
Numbers can be partitioned in different ways. Two-digit numbers can always be described using tens and ones.
Numbers can be partitioned in different ways. Two-digit numbers can always be described using tens and ones.
Learning routine: Build → Split → Name parts → Recombine → Explain
Other partitions are possible, such as 40 + 16, if the total stays 56.
Good mathematicians can split the same number more than one way.
Explain your thinking: Say what each part of the model represents, then explain why the answer or conclusion follows.
Partition a number in more than one way and check that its total stays the same.
Can 46 be shown as 3 tens and 16 ones?
| Representation | Tens | Ones | Total |
|---|---|---|---|
| Before regrouping | 4 | 6 | 46 |
| After opening one ten | 3 | 16 | 46 |
Watch for this mistake: Regrouping does not add or remove objects. Count the value of each bundle as ten, not one.
Complete: 35 is 2 tens and __ ones.
Open one of the 3 tens in 35.
15 ones. 20 + 15 = 35.
Which shows 28: 2 tens and 8 ones, or 1 ten and 8 ones? Explain.
Find the total in each representation.
2 tens and 8 ones. The other representation shows 18.
These curriculum examples extend the central model into varied contexts. They are learning contexts, not extra definitions to memorise.
building knowledge and understanding of the part-part-whole facts to 10, using physical and virtual materials; for example, using virtual ten-frames through a digital app or website to identify pairs of numbers that combine to make 10
Try and explain: A ten-frame has six filled spaces. How many empty spaces complete ten? Show the two parts.
Four spaces are empty. Six and four combine to make ten: 6 + 4 = 10.
using physical and virtual materials to partition numbers into counts of tens and ones; for example, recognise 35 as 3 tens and 5 ones or as 2 tens and 15 ones
Try and explain: Build 52 with tens and ones. Open one bundle of ten. How many tens and ones are there now?
Four tens and twelve ones. Opening a bundle changes the grouping, but 40 + 12 still equals 52.
using part-part-whole reasoning and physical or virtual materials to represent 24, then partitioning 24 in different ways and recording the partitions using numbers; for example, 10, 10 and 4 combine to make 24 or 10 and 14 combine to make 24
Try and explain: Show 28 as 20 and 8, then find a different split. How can you check it?
For example, 10 and 18. Recombine the parts: 10 + 18 = 28, just as 20 + 8 = 28.
Build 43 and split it into tens and ones.
Model: 43 = 40 + 3
Find two different partitions of 29.
Model: 29 = 20 + 9 = 10 + 19
Given 60 + 5, say and write the whole number.
Model: 60 + 5 → 65
Key idea: Numbers can be partitioned in different ways. Two-digit numbers can always be described using tens and ones.
Return to the concept model if an answer is uncertain. Use the model to explain, not just to guess.
AC9M1N02: partition one- and two-digit numbers in different ways using physical and virtual materials, including partitioning two-digit numbers into tens and ones
Use the Practice Sheet for written or hands-on work, Practice for supported feedback, and Test when the student is ready to demonstrate independent mastery.
The SkillrHub lesson remains the primary learning resource. This optional video reinforces the explanation; you can complete the lesson and practice without watching.
Before you watch:
Scratch Garden — See how a number can be split into parts, including a group of ten and some ones.
As you watch: Find two different ways to make the same total. Does the total change?
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Try it: Make 16 counters into ten and six. Rearrange them into eight and eight, then explain why both show 16.
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Mapped skill: partition one- and two-digit numbers in different ways using physical and virtual materials, including partitioning two-digit numbers into tens and ones
These references identify matching or closely related learning. Curriculum sequence, terminology and depth vary, so teachers should use the mapped skill and lesson difficulty to confirm suitability.
| Region | Curriculum framework | Closest level or code |
|---|---|---|
| Australia | Australian Curriculum v9.0 | AC9M1N02 · Year 1 |
| Victoria | Victorian Curriculum F–10 Version 2.0 — Mathematics | VC2M1N02 · Level 1 |
| New South Wales | NSW Mathematics K–10 Syllabus (2022) | MA1-RWN-02 · Stage 1 |
| United States (USA) | Common Core State Standards for Mathematics | Grade 1 |
| Canada (Ontario) | Ontario Curriculum — Mathematics | Grade 1 |
| United Kingdom (England) | National Curriculum in England — Mathematics | Year 2, Key Stage 1 |
| India | NCERT / CBSE — Mathematics | Class 1 |
Australian Curriculum v9.0 is the canonical source for this SkillrHub lesson. Victoria and NSW entries name the closest published state codes or outcomes; international entries are planning references rather than claims of identical curricula.
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Topic reference: AC9M1N02 — Partitioning Tens and Ones
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