(bubbly music playing) (buoyant music plays) (bubbly music playing) - [Kids] Math Mights.

(bubbly music) - Welcome second grade Math Mights, my name is Mrs. McCartney.

I'm so excited that you've joined us today for some more math.

Today we're gonna do a Mystery Math Mistake and then we're gonna look more at fractions, looking at fractions with a whole.

Let's start off first by warming up our math brain with our Mystery Math Mistake with the Math Mights.

(bubbly music plays) Oh no, what has happened to all of our Math Mights?

What are you doing Teapops, you're holding DC's hammer.

Oh my goodness, the Math Mights, are all mixed up and they need your help.

The Mystery Math Mistake works like this, one of our characters has solved a problem but he maybe didn't do it correctly, so you're gonna use your magnifying glass to see if you can find the Mystery Math Mistake that our character did from the Math Mights to help get them straight.

Let's check out to see what the problem is that one of our characters solved.

Hey, look, it's DC, he's upside down and all turned around.

I want you to watch closely as we solve this problem so you can see if DC made any mistakes.

DC as you know, loves to decompose numbers and find a friendly number, so he decided to decompose the 14 into four so he could bring it to the next decade and 10.

DC put the four with the 76 and made it a 70 and then added 10 more to make it 80.

What do you think?

Did you see where DC maybe made a mistake, were you following along?

He's not feeling very well and he's all messed up.

Let's see what our friends Shanda and Kelly think about the way DC solved that problem.

Shanda says something doesn't seem right with this problem.

Kelly said, if we added four to 76, it would be 80, not 70.

The new equation should be 80 plus 10, which is 90.

Let's see, did you find that same mistake that Kelly found?

Let's take a look and see what we have.

DC is right side up, he's feeling better now that he's gotten some of his friends help so we need to get to work and look at this problem.

We did do it correctly or DC decomposed this into four and 10, but the error was in his adding.

If we added four to the number 76, we would not get 70, we would get 80.

When we add the 80 plus the 10, the answer would not be 80, it would be 90.

Thanks so much for helping us with that Mystery Math Mistake.

Being able to find errors in math and being able to see them and talk about them is a really important skill as a second grader.

Let's check out our "I Can Statement" for the day.

Our I Can Statement says, I can make halves, thirds, and fourths different ways and discover a whole.

Let's take a look at these two rectangles.

Can you show different ways to split the rectangle into quarters or fourths?

Shade in one fourth of the rectangle.

Remember when we talk about fourths or quarters, we're partitioning the rectangle into four equal parts.

So we have to think about, can we do that more than one way?

Let's check out first to see how Shanda decided to partition her rectangle into fourths or quarters.

She decided to take the rectangle and split it this way.

She has four equal pieces and then she shaded in one of the fourths.

Can you think of a different way that you could partition a rectangle that's not the same as Shanda's but all the parts are still equal?

Let's see what Kelly thinks.

Whoa, Kelly has taken the rectangle and she's partitioned it a different way.

Let's take a look.

She divided it horizontally and put it into four equal parts.

She shaded one fourth of the fourths that she created.

Are these equal parts?

Yes, indeed.

Do you think that this piece is the same size as this piece?

We know by looking at both Shanda and Kelly's rectangles partition into fourths that those parts were equal.

Even though they were divided differently, as long as you're talking about the same whole that's been divided into four equal parts, it doesn't matter which way we divide them.

Do you think we can do this same idea looking at it with squares?

Let's take a look at these two squares.

Do you think that we can show two different ways to split the squares in half?

We wanna be able to shade one half of the squares.

Let's see first what our friend Shanda decided to do.

She decided to partition the square into two equal parts or halves, right?

And then she shaded a half of one of the sides.

Do you think we could partition that square a different way?

Let's see how Kelly decided to do hers.

It looks like she also partitioned it into two equal parts to make halves.

She shaded one half of it just like Shanda did, the same square is shaded into two pieces.

We're talking about the same size, whole, so we know that these two parts are equal.

Great job partitioning those squares in two different ways.

Sometimes when we think of fractions it helps us understand it by thinking of food.

Let's check out this problem.

Diego's dad made two square pans of cornbread and sliced them up for the family.

When they went to eat them, Diego's little brother was upset because he thought his piece of cornbread was smaller than Diego's, what would you tell him?

Look at that picture, the one on the left shows Diego's brothers slice, the one on the right shows Diego's slice.

Hmm, when you're looking at that, are you thinking that you might think the same thing?

That wait a minute, Diego's getting this really long slice and I'm just getting this small square slice.

Let's see what our friends Shanda and Kelly think of this.

Shanda says both pans are split into four equal parts, so you both got a quarter of the pan.

Since the pans are the same size, you both got the same amount.

That's a really great tip to remember when you're thinking of fractions.

If the whole is the same, and it's partitioned into the same parts regardless of how it's cut, they are still equal to that size that you cut it into.

Just like this one, if we compare Diego's slice and Diego's brothers slice, they're actually the same size 'cause they each got a quarter.

Let's take a look at this with the idea of pizza, man, this is making me hungry.

Clare and her friends are going to share a pizza.

What are some mathematical questions we can ask about this situation?

Have you ever shared a pizza with someone?

Let's see what some of the ideas that Shanda and Kelly have.

Shanda says, how many friends does she have?

How much pizza can each friend get?

Kelly asks, can they slice the pizza in a different way?

What would be a fair way to share the pizza with her friends?

Those are all really great questions.

When you order pizza, you probably have to think about this same idea.

Clare ate three slices and her friends got upset with her.

Hmm, I wonder why her friends got upset with her if they had a piece of pizza that they cut and she ate three slices, can't they eat any?

How many thirds did Clare eat?

How much pizza is left?

Shanda says Clare ate three thirds which is the whole pizza.

Kelly said she ate three thirds, so there isn't any pieces left.

Let's take a look at the pizza here.

I have it divided into three pieces, who knows how many friends she had, but if she said, hey, I wanna have a piece, I'm really hungry, I wanna have another piece, and then I wanna have another piece.

Oh-oh, I see why her friends were upset because she ended up eating three thirds of the pizza.

Let's think about what we know about fractions while we apply it to the pizza scenarios.

In this one, it says, if she want to share it with three friends, how many pieces of pizza would each person get?

If we look at this pizza and we have three friends, each person would get one third or one slice out of the three.

What happens if we were to try to share the pizza with just two friends?

Here I have a piece of pizza and if I wanted to split it into two parts 'cause I have two friends, one, wow, that'd be a really big piece, right?

One person would get half of the pizza and the other person would get half.

So if it's split into half, each person gets one slice of pizza.

What about if we took the pizza and we wanted to share it with four friends?

We would have to take the pizza and divide it into four equal parts.

This way, each person would get one slice of pizza or it would be one fourth of the pizza.

I don't know about you but thinking of a whole pizza, thinking about how many friends you have will tell you how many pieces you might wanna divide it in.

Let's see if we can apply our same thinking to a pie.

Let's take a look.

Do you think that you can use these four images, A, B, C and D to see if we can match it to a word problem?

This word problem said, Noah ate most of the pie.

He left a quarter of the pie for Diego.

Let's take a look at these pies.

When you see the gray, it's like the 10, so part of it has been eaten.

Do you think that one of these images might match what Noah ate?

Noah ate most of the pie.

When I look at this, this is full, there's a lot left, here's most of the pie, he left a quarter of it for his friend Diego.

I see one quarter of the pie left which means he ate the other three slices or the other three fourths.

Great job matching that word problem to the pie, let's try another one.

Tyler cut a pie into four equal parts.

He ate a quarter of the pie.

Which one of these images do you think matches that story?

It says he cut it into four equal parts, so I know C doesn't belong, I know A doesn't belong because it's in two equal parts, these are both cut into four equal parts.

It says that he ate one quarter of the pie, so this D would be the one that would show it, these three obviously are still left which anyone else could share that pie with him.

You did a great job.

Looking at those pies and really thinking about the word problem that applied to the picture.

Let's see if we can start to partition circles and have some language that we can use to figure out how much is shaded or not shaded.

Let's start off with our circle.

The first direction says, partition the circle into four equal parts.

I have a circle here and I'm gonna go ahead and partition it into four equal parts, kind of thinking of it like that pizza or that pie, we now have four equal parts.

The next part says shade in a quarter of the circle orange.

So we know that we have four equal parts, we want to shade in one quarter orange.

So I'm gonna take my orange marker and shade in this one out of the four.

The next part says, we need to shade in the rest of the circle blue.

Here we have the other pieces that we haven't shaded, so we're gonna shade each one of those parts blue.

Now that we have our circle filled in, let's see what the question is.

It says, how much of the circle is shaded by each color?

Do you think you could look at our circle and tell someone how much of the circle is orange and how much of our circle is blue?

Let's take a look.

We see that one out of the four, so one fourth of our circle is orange.

When we look at the blue we see one, two, three out of the total of the four is shaded blue, so three fourths are blue.

Great job on being able to use fraction parts and name them with the two different colors.

Now it's your turn to play version two of Split the Shape.

You're gonna be able to play it with a friend and see how you can partition shapes two different ways.

Boys and girls, I've had so much fun hanging out with you today on our Math Might show from our Mystery Math Mistake to help get DC straight.

And then we did so much with food it seemed like doing fractions.

I had a great time hanging out with you, I hope you'll join me again soon.

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- [Girl] Changing the way you think about math.

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