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Topmarks Maths

Topmarks Hit the Button number bonds maths mission

A practical mini-mission using number bonds to practise addition fluency through questions, examples and child-friendly challenges.

Quick answer

Number bonds are pairs of numbers that add up to a given total. Practising number bonds helps children become faster and more confident with addition and subtraction. The Topmarks Hit the Button game is a fun way to learn and practise these number bonds.

Learning outcome

By the end of this page, you will know how to find number bonds to 10 and 20, and you will be able to use them quickly in games and real life. Success signs:
  • You can say what number you need to add to make 10 or 20
  • You can play the Hit the Button game and get quick answers
  • You can use number bonds to help solve problems in your daily life
  • You can explain how number bonds help you add and subtract

Why this matters

Number bonds are a key part of maths that help children understand how numbers work together. When you know your number bonds, you can add and subtract numbers quickly without counting on your fingers. This skill helps in many areas:
  • It makes mental maths easier
  • It helps with solving word problems
  • It builds a strong base for learning bigger numbers
  • It makes games like Hit the Button more fun and faster to play

How it works

Number bonds are pairs of numbers that add up to a given total. For example, if the total is 10, then:
  • 1 + 9 = 10
  • 2 + 8 = 10
  • 3 + 7 = 10
  • 4 + 6 = 10
  • 5 + 5 = 10
These are all number bonds for 10. You can also find number bonds for 20:
  • 1 + 19 = 20
  • 2 + 18 = 20
  • 3 + 17 = 20
  • 4 + 16 = 20
  • 5 + 15 = 20
  • 6 + 14 = 20
  • 7 + 13 = 20
  • 8 + 12 = 20
  • 9 + 11 = 20
  • 10 + 10 = 20
To find a number bond, you need to think: "What number do I need to add to this number to get the total?"

Examples you can see

Let’s imagine you have 10 sweets and you want to share them with your friend. You might take 3 sweets, and your friend takes 7. That’s one number bond: 3 + 7 = 10. Another example: You are playing a game and your score is 15. If you want to get to 20, how many more points do you need? You need 5 more points because 15 + 5 = 20. Here is a table of number bonds to 10:
First Number Second Number Total
0 10 10
1 9 10
2 8 10
3 7 10
4 6 10
5 5 10
And here is a table of number bonds to 20:
First Number Second Number Total
0 20 20
1 19 20
2 18 20
3 17 20
4 16 20
5 15 20
6 14 20
7 13 20
8 12 20
9 11 20
10 10 20

Try it as a mini adventure

Adventure: The Number Bond Treasure Hunt You are on a mission to find treasure! The treasure map says you need to solve number bonds to find the hidden chest. You start with 10 coins and need to collect 10 more to open the chest. 1st time: You find 1 coin. How many more do you need? 9 more 2nd time: You find 2 coins. How many more do you need? 8 more 3rd time: You find 3 coins. How many more do you need? 7 more 4th time: You find 4 coins. How many more do you need? 6 more 5th time: You find 5 coins. How many more do you need? 5 more Keep going until you find all the number bonds to 10! Now try the same for 20 coins:
  • You find 1 coin. How many more do you need? 19 more
  • You find 2 coins. How many more do you need? 18 more
  • You find 3 coins. How many more do you need? 17 more
  • You find 4 coins. How many more do you need? 16 more
  • You find 5 coins. How many more do you need? 15 more

Common mistakes

  • Mistake: Thinking that 10 + 10 = 20, but not knowing that 10 + 9 = 19 or 10 + 8 = 18.
    Why it happens: Children might get confused by the idea that there are many pairs that make 10 or 20.
    Fix: Practice with pairs of numbers and use fingers or objects to see the total.
  • Mistake: Forgetting that 5 + 5 = 10.
    Why it happens: The same number added to itself is easy to forget.
    Fix: Use counting blocks or draw a picture to see 5 + 5 = 10.
  • Mistake: Not knowing what number to add to 7 to get 10.
    Why it happens: Children may not have memorised all number bonds yet.
    Fix: Use number lines or counting on fingers to figure out the answer.

Parent and carer guide

Parents and carers can help by:
  • Practising number bonds with flashcards or games
  • Using everyday situations to talk about number bonds (e.g., "If you have 5 apples and I give you 5 more, how many do you have?")
  • Playing the Hit the Button game together
  • Encouraging children to say number bonds out loud
  • Not worrying if they don’t get it right the first time
What to say:
  • "Let's find all the number bonds to 10 together!"
  • "You did a great job finding 4 + 6 = 10!"
  • "Can you try to find the number bond for 20?"
What not to worry about:
  • Children making mistakes – they’re learning!
  • They don’t know all number bonds yet – that’s okay!
  • They don’t play the game perfectly at first – practice makes progress!

Practice questions

  1. What number bonds to 10 can you find?
  2. What number do you add to 6 to make 10?
  3. What number bonds to 20 can you find?
  4. What number do you add to 12 to make 20?
  5. Find the number bond for 15 + ? = 20
Answers:
  1. 0 + 10, 1 + 9, 2 + 8, 3 + 7, 4 + 6, 5 + 5
  2. 4
  3. 0 + 20, 1 + 19, 2 + 18, 3 + 17, 4 + 16, 5 + 15, 6 + 14, 7 + 13, 8 + 12, 9 + 11, 10 + 10
  4. 8
  5. 5

FAQ

What are number bonds?

Number bonds are pairs of numbers that add up to a given total, like 3 + 7 = 10.

Why are number bonds important?

They help you add and subtract quickly and build a strong maths foundation.

How can I practice number bonds?

You can use games like Hit the Button, flashcards, or count objects like blocks or sweets.

Can I use number bonds for bigger numbers?

Yes! Once you know number bonds to 10 and 20, you can use them for larger numbers too.

What if I get confused with number bonds?

That’s normal! Keep practising, and use fingers, drawings, or objects to help you.