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Coding And Maths

Scratch maths: loops as repeated addition

Use Scratch projects to show how repeat blocks connect to skip counting and multiplication.

Quick answer

In Scratch, you can use the repeat block to show how multiplication works by adding the same number over and over again. This is called repeated addition, and it helps you understand how multiplication works in a fun, visual way.

Learning outcome

By the end of this page, you will understand how to use Scratch loops to show repeated addition, and how this helps you learn multiplication. Success signs:
  • You can explain what repeated addition means
  • You can use a Scratch project to show repeated addition
  • You can connect what you see in Scratch to real-life maths
  • You can solve simple multiplication problems using repeated addition

Why this matters

When you learn to code in Scratch, you can see maths in action. Using loops in Scratch helps you understand how multiplication works by showing the same action happening again and again. This makes multiplication easier to understand, and it helps you see how maths is used in games and digital projects. Whether you're making a game, designing a pattern, or counting your coins, repeated addition and loops help you think like a mathematician.

How it works

In Scratch, you can use the repeat block to make a sprite (like a character) do the same thing many times. Each time it does the thing, it’s like adding the same number again and again. This is how repeated addition works, and it helps us understand multiplication. Let’s imagine you are making a game where your character collects apples. If your character collects 3 apples each time, and it does this 4 times, you are adding 3 + 3 + 3 + 3. That’s the same as 3 × 4. In Scratch, you can use a loop to do this for you. Here’s how to do it:
  1. Choose a sprite (like a character or animal)
  2. Use a repeat block
  3. Set the loop to repeat the same action
  4. Each time the action happens, it’s like adding the same number
  5. Count how many times the loop runs to see the total

Examples you can see

Let’s use a simple example to show how this works in Scratch. Example 1: Collecting Coins Imagine a sprite collecting coins. Each time it collects a coin, it adds 1 to a total. If it collects coins 5 times, it adds 1 five times. That’s 1 + 1 + 1 + 1 + 1 = 5. In Scratch, you could write:
  1. Set a variable called "coins" to 0
  2. Repeat 5 times
  3. Add 1 to "coins"
  4. End repeat
The result is 5 coins. This is the same as 1 × 5 = 5. Example 2: Jumping on a Number Line Imagine a character jumping on a number line. Each jump is 2 spaces forward. If it jumps 4 times, it moves 2 + 2 + 2 + 2 = 8 spaces. That’s 2 × 4 = 8. In Scratch:
  1. Set a variable called "position" to 0
  2. Repeat 4 times
  3. Add 2 to "position"
  4. End repeat
The final position is 8. This is the same as 2 × 4 = 8. Example 3: Building with Blocks You’re building a tower with blocks. Each layer has 3 blocks. If you make 6 layers, you have 3 + 3 + 3 + 3 + 3 + 3 = 18 blocks. That’s 3 × 6 = 18. In Scratch:
  1. Set a variable called "blocks" to 0
  2. Repeat 6 times
  3. Add 3 to "blocks"
  4. End repeat
You now have 18 blocks. This is the same as 3 × 6 = 18.

Try it as a mini adventure

Adventure: The Magic Bakery You are a baker in a magical bakery. Every time you bake a batch of cookies, you make 4 cookies. You want to bake 5 batches. How many cookies will you have in total? Let’s make a Scratch project to help you solve this:
  1. Choose a sprite (like a cookie or a baker)
  2. Set a variable called "cookies" to 0
  3. Use a repeat block to repeat 5 times
  4. Inside the repeat, add 4 to "cookies"
  5. When the loop finishes, you’ll see how many cookies you have
Try this in Scratch and see how many cookies you make! Challenge: What if you make 3 batches, and each batch has 7 cookies? How many cookies will you have? Try it with your Scratch project!

Common mistakes

  • Mistake: Forgetting to start the variable at 0 before the loop
    Why it happens: The loop might add to a number that is not zero, causing wrong totals
    Fix: Always set your variable to 0 before starting the loop
  • Mistake: Thinking that the loop number is the same as the answer
    Why it happens: Children may think that if the loop runs 5 times, the answer is 5
    Fix: Remember that the loop runs a certain number of times, but you add a number each time
  • Mistake: Adding the wrong number in the loop
    Why it happens: A child might accidentally add 5 instead of 3
    Fix: Double-check what number you are adding each time

Parent and carer guide

If you are helping your child with this Scratch activity, here’s how you can support them:
  • Encourage them to explain what the loop is doing in their project
  • Ask them to predict how many times the loop will run and what the final number will be
  • Use real-life examples like sharing snacks or counting toys to connect the idea
  • Let them try different numbers to see how the totals change
  • Ask them to draw or act out the repeated addition before coding it
You can also use this time to show how loops in Scratch are like real-life patterns. For example, if they jump 3 times, then 3 more times, they are doing repeated addition. This helps them understand that maths is all around them.

Practice questions

  1. How many times do you repeat if you add 2 + 2 + 2 + 2 + 2?
  2. What is 4 × 3 shown as repeated addition?
  3. If you repeat 5 times and add 3 each time, what is the total?
  4. How many times do you repeat to show 6 + 6 + 6 + 6?
  5. What is 7 × 2 shown as repeated addition?
Answers:
  1. 5 times
  2. 3 + 3 + 3 + 3
  3. 15
  4. 4 times
  5. 2 + 2 + 2 + 2 + 2 + 2 + 2

FAQ

What is repeated addition?

Repeated addition is when you add the same number over and over again. It’s a way to show multiplication.

How does a loop in Scratch help with multiplication?

A loop in Scratch repeats the same action, which is like adding the same number multiple times. This shows how multiplication works.

Can I use loops for any multiplication problem?

Yes! You can use loops to show any multiplication problem by repeating the same addition.

Why is learning this useful?

It helps you understand how multiplication works, and it connects coding to maths in a fun way.

What if I don’t know my multiplication facts yet?

Using loops in Scratch helps you learn multiplication by seeing it happen step by step, so it’s a great way to build understanding!