# Lesson Video: Addition and Subtraction within 20 Using Bar Models Mathematics • 2nd Grade

In this video, we will learn how to use bar models to represent addition and subtraction story problems.

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### Video Transcript

Addition and Subtraction within 20 Using Bar Models

In this video, we will learn how to use bar models to represent addition and subtraction problems. We can use a bar model to help us solve an addition problem. Let’s try an example.

The question asks us to find the missing number: 11 plus seven equals the missing number.

The bar model represents an addition problem: 11 plus seven. There are 11 blue cubes in the model, and there are seven orange cubes. If we add the blue bricks and the orange bricks together, we can count the total number of bricks. We can start counting at 11 and count forward seven more: 11, 12, 13, 14, 15, 16, 17, 18. 11 and seven more makes 18 in total. 11 plus seven is 18.

Now let’s look at an example of a subtraction problem.

Find the missing number to make the equation correct: 13 take away six equals the missing number. The bar model shows us that there are 13 bricks at the start. And we need to take away six. This will give us the missing number. So if we take away six, how many will be left?

We need to count the number of blue bricks: one, two, three, four, five, six, seven. There were 13 bricks at the start. We took away six. Seven were left.

In this video, we’ve learned how to use bar models to help us solve addition and subtraction problems.