Number Bonds - A Guide for Parents

What are number bonds?

Number bonds have been called, at various points in the recent past, addition and subtraction facts, facts families, number stories and doubtless other names too. Parents are often unfamiliar with the names which sometimes causes concern, but they are simply combinations of numbers that fit together.

What do children need to know?

Children must know the number bonds that make 10.
10 can be made up out of:

  • 1 and 9
  • 2 and 8
  • 3 and 7
  • 4 and 6
  • 5 and 5

The feature video at the very top of this article shows all the addition number bonds to 10.

These addition bonds to ten are naturally related to the subtraction bonds to 10 as seen in this video:



If your child has instant recall of each of these number bonds and all of the ways they can fit together, they’ll be well on the way to dealing with arithmetic confidently and quickly. Ideally, they’ll also know their number bonds to 4, 5, 6, 7, 8 and 9.

Once your child has mastered these, the number bonds for numbers up to 20 are also useful to know – immediately knowing that (for example) 17 is made up of 8 and 9 makes subtraction much less fraught.

Number bonds the Singapore maths way


This video shows number bonds using the concept of "whole and parts" - an idea that comes from the Singapore maths programme.

Why are they important?

Knowing your number bonds fluently up to ten is one of the foundations to more complex arithmetic such as adding and subtracting with the ‘column methods’ and mental addition and subtraction to 100 and beyond.

They also help with addition and subtraction bridging 10. If you want to work out 16 – 8,  for example, you can use the following thought process:

  • 8 is made up of 6 and 2
  • 16 – 6 is 10, that’s easy
  • 10 is made of 8 and 2
  • 10 – 2 is 8
  • So 16 – 8 = 8

Next Steps

Now you understand exactly what number bonds (number fact families/number stories) are, and their importance as a bridge to more advanced maths skills, how well does your child know them? 

Our Kickstart Number bonds quizzes are a great (& free) way to find out. It's a quick quiz that's easy and fun for kids, but the clever bit is that parents receive instant and private feedback on how well their child did with suggestions to help them improve.


Take the Number Bonds Quiz


I’m Ged, Co-founder of Komodo, ex-maths teacher and dad. If you have any questions please get in touch.

About Komodo – Komodo is a fun and effective way to boost primary maths skills. Designed for 5 to 11 year olds to use in the home, Komodo uses a little and often approach to learning maths (15 minutes, three to five times per week) that fits into the busy routine. Komodo helps users develop fluency and confidence in maths – without keeping them at the screen for long.

Find out more about Komodo and how it helps thousands of children each year do better at maths – you can even try Komodo for free. 

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