Adding Double Digits On Ten Frames

Teacher: We are going to learn more about addition. What do you see when you look at this addition problem?
Student: I see one of the addends has two digits and the other addend has one digit!
Teacher: That’s right! We line up the numbers like this to show the tens digit and the ones digit of each number.
Student: Does that mean a two-digit number has a ones digit and a tens digit? And a one-digit number just has a ones digit?
Teacher: Exactly! When we add like this, we add the ones digit and then the tens digit.
Student: I’m not sure how to do that.
Teacher: That’s okay! We will use ten frames to help us.
Student: Oh great! I’m excited to try this out!
Teacher: Wonderful! Here is a piece of paper with the addition problems and ten frames. Let’s start with the first problem.
Student: 11 plus 2. I know 11 has 1 one and 1 ten. That’s why there’s a 1 for the ones digit and a 1 for the tens digit.
Teacher: Yes! Now we need to add 2. You can use the ten frames and these crayons to help you. Let’s use blue for the first addend and red for the second addend.
Student: Okay! I’ll color 11 spaces blue. I’ll color 2 spaces red. Here’s one full ten frame and 3 more. 10, 11, 12, 13!
Teacher: Great job! 11 plus 2 is 13. Look at the addition problem. If we added the ones digits, we would add 1 plus 2 to get 3. Then, we would add the tens digits. 1 plus 0 is 1. The empty space is a 0. That’s why the 3 goes here and the 1 goes here when we write the sum.
Student: I see! It’s like two addition problems. We add the ones digits and write the sum below them. Then, we add the tens digits and write the sum below them!
Teacher: You’ve got it! Let’s try the next problem.
Student: 15 plus 3. 15 has a 5 for the ones digit and a 1 for the tens digit. I want to try the addition problem first. I’ll add 5 and 3. That’s 8! Do I write the 8 here?
Teacher: Yes! What about the tens digits?
Student: There’s just a 1 here. That’s 1 plus 0, which is 1. I’ll write the 1 here. 15 plus 3 is 18!
Teacher: Now try using the ten frames.
Student: I’ll color in 15 spaces blue and 3 spaces red. That’s one full ten frame and 8 more. 10, 11, 12, 13, 14, 15, 16, 17, 18. I got 18! Just like when we added.
Teacher: That’s right! You did a great job adding the ones digits and tens digits!