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addition

Addition misconceptions

Fix errors such as counting all, misaligning columns and ignoring regrouping.

Quick answer

Addition misconceptions happen when children misunderstand how to add numbers, like counting everything instead of combining groups, misaligning numbers, or ignoring regrouping. You can fix these mistakes by learning to use place value, align numbers correctly, and understand that regrouping is needed when you have more than 9 in any column.

Learning outcome

By the end of this page, you will understand how to add numbers correctly by using place value, aligning numbers properly, and knowing when to regroup. Success signs:
  • You can add two 2-digit numbers without making mistakes
  • You can explain why you need to regroup when adding
  • You can spot when someone has made an addition mistake
  • You can use place value to check your answers

Why this matters

Addition is one of the first maths skills children learn, and it’s used everywhere in daily life. Whether you’re sharing snacks, counting coins, or adding up your points in a game, understanding how to add correctly helps you solve problems quickly and confidently. In school, addition skills build up to more complex maths like subtraction, multiplication, and division. If you have a misunderstanding about how to add, it can make all future maths harder. That’s why it’s important to learn the right way from the start.

How it works

To add numbers correctly, follow these steps:
  1. Align the numbers by place value (ones under ones, tens under tens, etc.)
  2. Add the ones column first
  3. If the total is 10 or more, write the ones digit and carry the tens digit
  4. Add the tens column, including any carried number
  5. Check your answer using place value or by counting again

Examples you can see

Let’s look at a simple example: 24 + 17.
Ones Tens
4 2
7 1
First, add the ones: 4 + 7 = 11. Write down 1 and carry 1 to the tens column. Then add the tens: 2 + 1 + 1 (carried) = 4. So, 24 + 17 = 41. Let’s try another one: 36 + 28.
Ones Tens
6 3
8 2
Add the ones: 6 + 8 = 14. Write down 4 and carry 1. Add the tens: 3 + 2 + 1 (carried) = 6. So, 36 + 28 = 64. You can also think of this with objects. Imagine you have 36 counters and 28 more. If you group them into tens and ones, you can count them easily and see that 36 + 28 = 64.

Try it as a mini adventure

Adventure: The Treasure Hunt You are on a treasure hunt with your friends. You find two clues: Clue 1 says: "Add 24 coins to your collection." Clue 2 says: "Then add 17 more coins." You start with 0 coins. How many coins do you have now? Let’s solve this step by step:
  1. You start with 0 coins
  2. Clue 1: Add 24 coins. You now have 24 coins
  3. Clue 2: Add 17 more coins. You now have 24 + 17 coins
  4. 24 + 17 = 41 coins
So, you have 41 coins in total. That’s enough to buy a small toy!

Common mistakes

  • Mistake: Counting all numbers instead of combining groups Why it happens: The child doesn’t understand that addition means putting groups together. Fix: Use objects like blocks or counters to show that 3 + 2 means 3 things and 2 more things, not 5 separate counts.
  • Mistake: Misaligning numbers when adding vertically Why it happens: Children don’t understand place value or forget to line up the digits. Fix: Always write numbers so that ones are under ones, tens under tens, etc. Use a place value chart to help.
  • Mistake: Forgetting to regroup when the sum in a column is 10 or more Why it happens: Children think they can just write the full number in the column. Fix: Teach that 10 ones make 1 ten. Always carry the 1 to the next column.
  • Mistake: Adding from left to right instead of right to left Why it happens: Some children think it’s easier to start with the bigger number. Fix: Practice adding from right to left, starting with ones, then tens, and so on.

Parent and carer guide

Parents and carers can help by:
  • Using physical objects like blocks, counters, or coins to show addition
  • Practising place value with number charts or place value games
  • Checking that numbers are lined up correctly when adding
  • Encouraging children to explain their thinking out loud
  • Using real-life situations to make addition fun, like counting snacks or adding up points in a game
  • Noticing if a child is struggling with regrouping and offering extra practice
Here are a few simple ways to help at home:
  1. Set up a small addition challenge with everyday items like apples or toys
  2. Play a game where you add up scores in a board game or card game
  3. Use a place value chart to help your child align numbers
  4. Ask your child to explain how they solved a problem
  5. Use a calculator to check answers after working out by hand

Practice questions

  1. What is 23 + 19?
  2. What is 45 + 37?
  3. What is 62 + 28?
  4. What is 14 + 36?
  5. What is 51 + 29?
Answers:
  1. 42
  2. 82
  3. 90
  4. 50
  5. 80

FAQ

What is the best way to teach addition?

The best way is to use visual aids like blocks or counters, teach place value, and encourage children to explain their thinking. Always start with simple numbers and build up gradually.

Why is it important to align numbers when adding?

Aligning numbers helps children use place value correctly. When ones are under ones, tens under tens, it makes it easier to add and regroup properly.

What should I do if my child keeps forgetting to regroup?

Use repeated practice with visual aids like base-10 blocks or place value charts. Practice with simple sums first, then gradually increase difficulty.

How can I make addition fun for my child?

Use games, real-life examples, and stories. Try adding up points in a game, counting snacks, or using a treasure hunt theme to make it exciting.

What are some signs that my child understands addition?

Your child can add numbers without counting on fingers, align numbers correctly, explain their thinking, and check their answers using place value.