Learning to round 3-digit numbers to the nearest hundred (Grade 3 lesson)

📚 Understanding Rounding to the Nearest Hundred

Rounding helps us simplify numbers to make them easier to work with. When rounding to the nearest hundred, we look at the tens digit to decide whether to round up or down. Think of it like this: numbers closer to the next hundred go up, and those closer to the previous hundred stay down.

• 🔍 Identify the Hundreds Digit: This is the digit in the hundreds place (e.g., in 342, the hundreds digit is 3).
• 👀 Look at the Tens Digit: This is the digit to the right of the hundreds digit (e.g., in 342, the tens digit is 4).
• ⚖️ Rounding Rule:
  • If the tens digit is 0, 1, 2, 3, or 4, we round down to the previous hundred.
  • If the tens digit is 5, 6, 7, 8, or 9, we round up to the next hundred.

✏️ Examples of Rounding

Let's go through a few examples to make this clearer:

• 🌱 Example 1: Round 342 to the nearest hundred.
  • Hundreds digit: 3
  • Tens digit: 4
  • Since 4 is less than 5, we round down to 300.
• 🌳 Example 2: Round 678 to the nearest hundred.
  • Hundreds digit: 6
  • Tens digit: 7
  • Since 7 is greater than or equal to 5, we round up to 700.
• 🌻 Example 3: Round 250 to the nearest hundred.
  • Hundreds digit: 2
  • Tens digit: 5
  • Since 5 is equal to 5, we round up to 300.

💡 Tips for Rounding

• 🧠 Number Line: Visualize a number line. Is the number closer to the lower hundred or the higher hundred?
• ✍️ Practice: The more you practice, the easier it becomes!
• 🌟 Think Money: Imagine you have $342. Do you have closer to $300 or $400?

📝 Practice Quiz

Round each of the following 3-digit numbers to the nearest hundred:

1. 415
2. 782
3. 139
4. 950
5. 222
6. 567
7. 809

✅ Solutions:

1. 400
2. 800
3. 100
4. 1000
5. 200
6. 600
7. 800