Mentally Adding 10 Worksheets for Grade 2 (3-Digit Numbers)

➕ Topic Summary

Mentally adding 10 to a 3-digit number is a simple trick that makes math easier! You just need to focus on the tens place. For example, if you have 234 and want to add 10, you only change the 3 in the tens place to a 4, making it 244. If the tens place is a 9, adding 10 will change the hundreds place as well (e.g., 392 + 10 = 402). Practice makes perfect!

This skill is important because it helps build number sense and mental math abilities. It's a foundational skill for more complex arithmetic later on.

🔤 Part A: Vocabulary

• 🔍Digit: A symbol used to represent a number.
• ➕Addition: The process of combining numbers.
• 💯Hundreds Place: The third digit from the right in a number.
• 🔟Tens Place: The second digit from the right in a number.
• 🧠Mental Math: Doing math in your head without writing it down.

✍️ Part B: Fill in the Blanks

When mentally adding 10 to a 3-digit number, focus on the __________ place. If the digit in that place is less than 9, simply __________ it by 1. If it is a 9, then you need to carry over to the __________ place.

🤔 Part C: Critical Thinking

Explain in your own words why it's helpful to be able to add 10 mentally to a 3-digit number. Can you think of a real-life situation where this skill might be useful?