Question Video: Adding Four-Digit Numbers Using Bar Models Mathematics

Video Transcript

Olivia and Jennifer want to represent 6,755 plus 2,648 on a bar model. Olivia used this bar model. Jennifer used this one. Who used the correct bar model? What is the result of 6,755 and 2,648?

Olivia and Jennifer are trying to represent 6,755 plus 2,648. We don’t know what the whole amount or the total is, but we do know both of the parts. One of the parts is 6,755, and the other is 2,648. So the correct bar model needs to show our two parts, 6,755 and 2,648. This is Olivia’s bar model. The first part is 6,755 which is one of our parts, and the second part is 2,648 which is our second part. And Olivia’s drawn a question mark because we don’t know the total. This looks like the correct bar model.

This is Jennifer’s bar model. Her bar model shows one of our parts, 2,648, but the other part is missing. This part should say 6,755. It looks like Jennifer’s written this as the whole amount. She’s written this number in the wrong place. So the person who used the correct bar model is Olivia. Now, we need to find the result of 6,755 plus 2,648. And we can use the standard written method or column addition to help find the result. Let’s start by adding the ones. Five ones and eight ones gives us a total of 13 ones, so we need to exchange. Now we can add the tens. Five 10s plus four 10s is nine 10s and one more makes 10 10s. Again, we need to exchange.

Now we can add the hundreds. Seven 100s and six 100s gives us 13 100s plus the one we exchanged gives us a total of 14 100s. And we need to exchange again. Finally, we can add the thousands. Six plus two is eight plus the one we exchanged gives us a total of nine 1,000s. 6,755 plus 2,648 equals 9,403. Olivia and Jennifer wanted to represent 6,755 plus 2,648 using a bar model. Olivia drew the correct bar model, and the result of 6,755 and 2,648 is 9,403.