Number bonds are one of the most powerful early maths concepts a child can learn, yet many parents are unfamiliar with the term. Understanding number bonds transforms how a child thinks about addition and subtraction, making both operations dramatically faster and more flexible.
What are number bonds?
A number bond is a pair of numbers that add together to make a target number. The number bonds to 10 are: 0+10, 1+9, 2+8, 3+7, 4+6, 5+5, 6+4, 7+3, 8+2, 9+1, 10+0.
The key insight is not just that these pairs add to 10: it is that knowing any one of them instantly gives you the others. If a child knows 7+3=10, they also know 3+7=10, 10-7=3, and 10-3=7 without any additional learning. One fact is four facts.
This is why early maths education focuses so heavily on number bonds. They are the most efficient investment in arithmetic fluency available at ages 4-7.
Number bonds to 10 and 20
Number Bonds to 10 is designed to make this foundational knowledge automatic through repeated, game-format practice. Children see a number and must quickly identify its pair that completes 10. The speed of response is the key metric: the goal is not just getting it right, but getting it right instantly.
Number Bonds to 20 extends the same principle to pairs that total 20. This is the natural next step and directly supports mental addition with larger numbers.
Children who have automatic recall of number bonds to 10 and 20 perform measurably faster at mental addition throughout primary school, according to research from the National Numeracy Strategy. The automaticity is the key: slow recall provides far less benefit than instant recall.
How number bonds support later maths
The benefits of number bond fluency extend far beyond simple addition:
Column addition: When adding 47 + 36, knowing that 7+6=13 instantly allows the child to focus on the column structure rather than the basic fact.
Subtraction: Number bonds make subtraction reversible. Knowing 4+6=10 means immediately knowing 10-6=4 without calculation.
Mental maths: Strategies like “making 10” rely entirely on number bond knowledge. To add 8+5 mentally, a fluent child makes it 8+2+3 = 10+3 = 13. This strategy requires instant knowledge of the bond 8+2=10.
Money: Making change from 10 pence or 20 pence directly uses number bonds.
Games vs. worksheets for number bonds
Number bonds are one of the areas where games have a clear advantage over worksheets. The instant feedback of a game (right away you know if 7+? was 3 and not 4) prevents the consolidation of wrong answers that can happen on a worksheet that is not marked immediately.
The repetition games provide is also better structured for memory: multiple short encounters with the same facts across multiple sessions, rather than many encounters in one session. This spaced repetition is the most efficient way to build automatic recall.
When to practise and for how long
Short daily sessions are dramatically more effective than occasional long ones for number bonds. Five minutes per day, five days per week, produces much stronger automaticity than 25 minutes once per week, because the spacing between sessions is what builds durable long-term memory.
Ages 4-6: Practise number bonds to 10. Goal is instant recall of all 11 pairs. Ages 6-8: Practise number bonds to 20. Goal is instant recall across both sets.
Games on KidsGames for number bonds
All free, no login, ideal for ages 4-8:
- Number Bonds to 10: Direct number bond practice in a game format. The essential starting point for all children under 7.
- Number Bonds to 20: Extended number bond knowledge. The natural follow-on once bonds to 10 are automatic.
- Addition Adventure: Number bonds in context with full addition problems. The bridge from isolated fact practice to applied addition.
- Count the Animals: Concrete counting that supports number bond understanding by grounding numbers in quantities.
Five minutes on Number Bonds to 10 tonight. If your child hesitates on more than two or three bonds, this is exactly where their maths practice should focus.