Relating Addition and Subtraction

✨ Section 1: What Does “Relating” Mean in Math?

When we say two math operations are “related,” it means they are connected or work together.

In Grade 1, we learn that addition and subtraction are opposites — but they use the same numbers.

🔁 Section 2: How Are Addition and Subtraction Related?

Let’s look at a simple number fact:

3 + 2 = 5
That means: If you put 3 and 2 together, you get 5.

Now look at this:

5 – 2 = 3
That means: If you take 2 away from 5, you go back to 3.

🧠 They are using the same numbers, just in a different way.

💡 Section 3: Let’s Try a Fact Family

A fact family is a group of 3 numbers that go together in 4 ways:

Example: 2, 3, and 5

• 2 + 3 = 5
  
  

• 3 + 2 = 5
  
  

• 5 – 2 = 3
  
  

• 5 – 3 = 2
  
  

These 4 facts are related because they all use the same numbers!

🎯 Section 4: Why Is This Important?

Learning how addition and subtraction are connected helps you:

• Solve problems faster
  
  

• Check your answers
  
  

• Think flexibly in math
  
  

• Understand how numbers work together
  
  

🧠 Section 5: Big Tip

If you know an addition fact, you can flip it into a subtraction fact — and vice versa!

For example:

• Know that 6 + 4 = 10?
  👉 Then you also know 10 – 6 = 4 and 10 – 4 = 6
  
  

🔢 Section 6: Try These Fact Families

Use the 3 numbers to write 2 addition and 2 subtraction facts:

1. 4, 5, 9
   
   

2. 6, 2, 8
   
   

3. 7, 3, 10
   
   

Answer Key:

• 4 + 5 = 9
  
  

• 5 + 4 = 9
  
  

• 9 – 4 = 5
  
  

• 9 – 5 = 4
  
  

• 6 + 2 = 8
  
  

• 2 + 6 = 8
  
  

• 8 – 2 = 6
  
  

• 8 – 6 = 2
  
  

• 7 + 3 = 10
  
  

• 3 + 7 = 10
  
  

• 10 – 3 = 7
  
  

• 10 – 7 = 3
  
  

📘 Section 7: Word Problem Example

Lily had 6 apples. She picked 4 more. Then she gave 4 to her friend.

• What is the total she picked? 6 + 4 = 10
  
  

• What if she gives 4 away? 10 – 4 = 6
  
  

👉 Addition brings us up, subtraction brings us back. They are part of the same story.