X Tables
Age Guides

Age 7 guide to two-digit methods

Age-appropriate activities, explanations and practice ideas for two-digit methods.

Quick answer

By the end of this page, you'll understand how to add and subtract two-digit numbers using methods that make sense, like breaking numbers into tens and ones, using number lines, or drawing pictures.

Learning outcome

By the end of this page, you will be able to add and subtract two-digit numbers using clear, visual methods that help you understand what's happening with the numbers. Success signs:
  • You can split a two-digit number into tens and ones
  • You can use a number line to add or subtract
  • You can draw pictures or use objects to show your work
  • You can solve problems like 47 + 32 or 85 - 24

Why this matters

Learning how to add and subtract two-digit numbers is like learning the secret codes that help you solve bigger problems. You'll use these skills when you're counting money, measuring things, or working out how many cookies you have left after sharing. It's also the foundation for learning more complex maths in the future, like multiplication and division.

How it works

We'll learn two main ways to work with two-digit numbers:
  1. Breaking numbers into tens and ones – This means splitting a number like 34 into 30 and 4
  2. Using a number line – This is like a path that helps you jump forward or backward
Let's start with breaking numbers into tens and ones because it's like sorting your toys into groups.

Examples you can see

Let's imagine you're at the park and you have 23 balloons, and your friend gives you 15 more. How many balloons do you have now? Method 1: Breaking into tens and ones
  • 23 = 20 + 3
  • 15 = 10 + 5
  • Add the tens: 20 + 10 = 30
  • Add the ones: 3 + 5 = 8
  • Now add the parts together: 30 + 8 = 38
Method 2: Using a number line
  • Start at 23
  • Jump forward 10 to get to 33
  • Jump forward 5 more to get to 38
Here's another example with subtraction. You have 56 stickers, and you give 24 to your sister. How many do you have left?
  • 56 = 50 + 6
  • 24 = 20 + 4
  • Subtract the tens: 50 - 20 = 30
  • Subtract the ones: 6 - 4 = 2
  • Add the parts together: 30 + 2 = 32

Try it as a mini adventure

Adventure: The Treasure Hunt You're on a treasure hunt! You start at the big tree and need to find clues. The first clue says "Go 27 steps forward, then 13 more steps." How many steps in total? Step 1: Split 27 into 20 + 7 Step 2: Split 13 into 10 + 3 Step 3: Add the tens: 20 + 10 = 30 Step 4: Add the ones: 7 + 3 = 10 Step 5: Add the totals: 30 + 10 = 40 You've walked 40 steps! The next clue is hidden at step 40. Try this again with:
  • 15 steps, then 28 more steps
  • 32 steps, then 17 more steps

Common mistakes

  • Mistake: Adding tens and ones together without separating them first Why it happens: It's easier to think of numbers as one big number, not parts Fix: Always split the numbers first into tens and ones, then add or subtract the parts
  • Mistake: Forgetting to regroup when you have more than 10 ones Why it happens: You might think 8 + 5 = 13, but not know to make a new ten Fix: If you get more than 10 ones, make a new ten and write the extra ones in the ones column
  • Mistake: Using a number line but jumping in the wrong direction Why it happens: Adding means going forward, subtracting means going backward Fix: Remember: Add = forward, Subtract = backward

Parent and carer guide

You can help your child by:
  • Using everyday situations to practice, like counting toys or snacks
  • Encouraging them to explain their thinking out loud
  • Letting them draw pictures or use objects to show their work
  • Practicing with simple problems first before moving to harder ones
  • Not rushing – it's okay to take time to understand the methods
If your child gets stuck, ask questions like:
  • Can you split the numbers into tens and ones?
  • What happens if you use a number line?
  • Can you show me with blocks or drawings?
Remember, it's normal to make mistakes – they help you learn!

Practice questions

  1. What is 34 + 25?
  2. What is 67 - 23?
  3. What is 42 + 18?
  4. What is 75 - 39?
  5. What is 26 + 37?
  6. What is 81 - 45?
  7. What is 53 + 29?
  8. What is 92 - 56?
Answers:
  1. 59
  2. 44
  3. 60
  4. 36
  5. 63
  6. 36
  7. 82
  8. 36

FAQ

What does it mean to break a number into tens and ones?

It means splitting a number into how many tens and how many ones it has. For example, 45 = 40 + 5.

Why do we split numbers into tens and ones?

It makes adding and subtracting easier because we can work with smaller parts.

Can I use a number line for subtraction?

Yes! To subtract, you move backward on the number line.

How can I practice at home?

You can use everyday items like coins, blocks, or toys to add and subtract.

What if I still get confused with two-digit numbers?

That's okay! Keep practicing with drawings, objects, and simple problems until it feels easier.