Number bonds: what they are and why they matter
By the BrightHop team · Published · Updated
Short answer
A number bond is a pair of numbers that make a whole, such as 7 and 3 making 10. Children who know their bonds to 10 can add, subtract and find missing numbers by reasoning instead of counting every time. It is one of the most useful early maths skills because later skills build on it.
What a number bond is
A number bond is two parts that make a whole. 7 and 3 make 10, so 7 + 3 = 10 and 3 + 7 = 10. Knowing one part means knowing its partner: the partner of 7 in 10 is 3.
| Part | Partner |
|---|---|
| 0 | 10 |
| 1 | 9 |
| 2 | 8 |
| 3 | 7 |
| 4 | 6 |
| 5 | 5 |
The other half of the table is the same pairs reversed (6 and 4, 7 and 3, and so on).
Why they matter
- Adding: 8 + 5 becomes 8 + 2 + 3, using the bond to reach 10.
- Subtracting: 10 − 7 is the same question as 'what goes with 7 to make 10?'
- Missing numbers: 7 + ? = 10 asks for the partner directly.
The Year 1 Australian Curriculum describes adding and subtracting within 20 using part-part-whole knowledge to 10. See the sources below.
Common mistakes
- Adding the part to 10: answering 17 for 'what goes with 7 to make 10?'
- Choosing a pair that makes 9 or 11, such as 6 and 3.
- Missing a split when listing all the ways: forgetting 0 and 10.
- Thinking 3 and 7 is the same split as 7 and 3, when the two groups are in different places.
These are the mistakes BrightHop's number bonds lesson looks for.
How to practise at home
- Draw a ten frame. Colour 7 spots and count the empty ones.
- Hold up fingers: 'I am showing 6. How many are hiding?'
- Cover part of a row of 10 objects and ask how many are hidden.
- Check every answer by adding the two parts back to 10.
Short and often works better than a long session. If bonds are secure and missing-number questions still fail, see why a child can add but not solve missing-number questions.
Try it
The free addition Skill Check includes missing-number questions that rely on number bonds, and shows whether bonds are worth revisiting.
Try the free addition Skill CheckFrequently asked questions
When should a child know their number bonds to 10?
The Year 1 curriculum works with part-part-whole knowledge to 10, so Year 1 is when most children are building it. Fluency is expected to grow across Years 1 and 2.
Are number bonds the same as times tables?
No. Number bonds are about adding and splitting a whole. Times tables are about equal groups.
Related guides
Sources
- Australian Curriculum v9: Mathematics, Year 1 (ACARA)
- Mathematics K–2 syllabus (2022) (NSW Education Standards Authority)
This guide is written by the BrightHop team from BrightHop’s own teaching approach. It is not independent research and not official curriculum guidance. Curriculum and research statements link to their original sources above. Skill Checks are informal and do not replace a teacher’s advice. About BrightHop