How to Find the Missing Number in a Simple Addition Equation

1. What We're Solving:

We need to find the missing number (represented by □) that makes this equation true: 3 + □ = 8

2. The Approach:

This is like a number puzzle! We're looking for what number, when added to 3, gives us 8. Think of it as asking "3 plus what equals 8?" We can solve this by thinking about what's missing or by using subtraction to "undo" the addition.

3. Step-by-Step Solution:

Method 1: Think about it logically

• We start with 3
• We need to get to 8
• So we ask: "What do I need to add to 3 to reach 8?"
• Count up from 3: 3... 4, 5, 6, 7, 8
• That's 5 more numbers! So □ = 5

Method 2: Use subtraction to "undo" the addition

• We have: 3 + □ = 8
• To find □, we can subtract 3 from both sides
• □ = 8 - 3
• □ = 5

Let's check our answer:

• 3 + 5 = 8 ✓
• Yes! It works!

4. The Answer:

□ = 5

The complete equation is: 3 + 5 = 8

5. Memory Tip:

Think of equations like a balanced scale! If you have 3 on one side and need 8 total, you can always subtract to find the missing piece: 8 - 3 = 5. This "opposite operation" trick works for all addition problems with missing numbers!

Great job working through this! You're building the foundation for solving more complex algebra problems. 🌟