Using The Bar Model For “Less Than” Or “Fewer” Comparison Problems

Hi, I'm Zoe, and in this video.

We'Re going to be looking how we can use the bar model to solve more complex comparison problems, ones that involve subtraction.

In the previous video, we looked at.

Addition, and because of the inverse relationship between addition and subtraction, if you haven't.

Watched that video yet, I suggest you watch it because we're going to be.

Using some of those methods. Here's the question we're going to be looking at.

Charlotte has baked six fewer cupcakes than Stuart. In total, they baked 32 cupcakes altogether.

How many cupcakes did each person bake?

Again, we've got relationship between two things.

And the overall total.

So we're going to start with Charlotte. Charlotte has baked some cupcakes. We've got a question mark. That is our unknown.

We don't know how many Charlotte has baked now because addition and subtraction are related and an inverse relationship, we know.

Charlotte has six fewer. This also means Stuart, looking at it.

From the other side, has six more cupcakes.

So Stuart starts with the same number of cupcakes as Charlotte, but he has baked six more cupcakes altogether. They have baked 32 cupcakes.

We're now into a similar method we.

Used for our addition. 32 take away 6 will give us.

How many left for our two unknowns.

So 32 take away 6 is 26.

Now, our two bars that are equal.

Make 26, so we can half that. 26 divided by 2 is 13. This is our unknown.

We can go back to our model and replace our question mark.

So Charlotte baked 13 cupcakes, a baker's dozen. And Stuart baked 13 cupcakes plus the.

Six more that he had. So 13 plus six is 19 cupcakes. So Stuart has baked 19.

Charlotte has baked 13. She has six fewer.

Looking back at the question, and we can add those together to check, they make 32. And that's how we use our bar model to solve complex comparison problems.