(bright music) (bells chime) (spring boings) (animation whooshes) - [Children] Math Mights.

- Hey, first grade Math Mights, welcome back.

And if it's your first time here, I'm Mrs. Markavich, and I'm so excited that you're here with me today.

Let's check out our plan for the day.

Today we'll be doing a number talk and then we'll be talking about triangles, rectangles and squares.

Let's warm up our math brain with a number talk.

A number talk is when I give you a problem with an operation that you're already familiar with and then you're going to try and solve it mentally.

That means in your brain without any paper or pencil.

And then you'll share out how you solved, explaining the strategy that you used.

I have a character here from Mathville to help me out today.

I wonder who it is.

(bright music) It's my favorite character, it's DC.

DC likes friendly numbers and he likes to decompose numbers.

He wears a hard hat and has a hammer or a mallet to smash the numbers into friendly numbers.

Let's take a look at our problem that we have today.

Our problem is 9 plus 6 equals hmm.

I wonder how you're thinking about solving this problem mentally.

Let's see what one of my friends has to say.

My friend Sira says, "I think the answer is 15 "because I decomposed 6 into 1 and 5 to make a 10.

"Then I added the 5 to the 10 to get 15."

Let's take a look at my double 10-frame mat and whiteboard and see what that looks like.

You can see that I have 9 built on the top and 6 on the bottom.

And then Sira said she decomposed the 6 into 1 and 5 to make a 10.

So I'm gonna take this 1 and move it to the top of my double 10-frame mat.

Now you can see the 10 and the 5 down here and that gives us 15.

If I were to solve it paper and pencil, I know we're doing this mentally, but this is what it would look like paper pencil.

I would decompose the 6 into 1 and 5.

My 9 would grab that 1 to make a 10 and then I would have 10 plus 5 equals 15.

I wonder if you solved it the same way that my friend Sira solved it.

If you did, great work.

Let's check out our I Can statement of the day.

It says, "I can explore what makes a shape "a triangle, a rectangle, and a square."

Let's take a look at these shapes.

I wonder which one you think doesn't belong.

I wanna see what my friends Sira and Tiffany think, and how funny is this, Math Mights?

You call me Mrs. Markavich, but my first name is actually Tiffany too.

Anyways, Sira says, "A is the only one that does not have straight lines."

And Tiffany says, "B is the only one that does not show one shape."

I happen to have these shapes in front of me.

Let's take a look at them.

Here you can see where Sira said shape A is the only one that doesn't have straight lines, and you can see right here there are curves in this shape.

But all the other shapes on this paper all have straight lines.

So she's right.

That shape might not belong.

Tiffany said B is the only one that does not show one shape.

I think she's got something there because when you look at this you can see A is just one shape, C is just one shape, D is just one shape, but when I look at this I actually see two shapes.

I see two triangles.

So she might be on the right track as well.

B might not belong.

I wonder if there are any other ways that you're thinking of shapes on this page that might not belong.

I think the girls have a couple more ideas.

Let's see what they have to say.

Sira says, "C is the only one that is a triangle."

And Tiffany says, "D is the only one that is not a closed shape."

Let's take a look at mine again.

Sira's right, we did say we saw two triangles here, but we also said it was two shapes.

C is actually the only one that is just one triangle.

And Tiffany said D is the only one that is not a closed shape.

And if you look closely at it, it looks like they forgot to finish drawing the line, so we call that an open shape.

Again, both girls have great ideas as to why the shapes they chose may not belong.

I wonder if you came up with any of the same thoughts and ideas that they had.

Math Mights, now we're going to take a look at triangles and not triangles.

Well, that's interesting.

What's the difference between a triangle and a not triangle?

Well, we know that triangles all have three sides and they all have three corners, so when you're looking at these you have to really dig deep and see which ones are triangles and which ones aren't.

I pulled some out for us.

They look like this.

We wanna talk about what is the same about all of these triangles.

And my friends Sira and Tiffany are here to do that with us.

Sira says, "I see they all have three sides."

And Tiffany says, "I see they all have three corners."

So if you look at mine, you can see that the triangles have one, two, three, one, two, three, one, two, three, one, two, three sides.

No matter how big or how small, how wide or skinny the triangle is, it still has three sides and three corners.

Corners are the pointy parts.

And if you're a real mathematician, you might call those corners vertices.

They are like this.

One, two, three.

One, two, three.

One, two, three.

One, two, three.

They all have three corners or vertices.

Great work, Math Mights.

What makes these shapes different from the triangles that we just saw?

I'm thinking that these are the not triangles.

They definitely look a little bit different.

Let's see what my friends Sira and Tiffany think.

Sira says, "They don't all have three sides."

And Tiffany says, "One isn't a closed shape.

"Some sides aren't straight."

If we take a closer look at them, we can see exactly what the girls are talking about.

I wonder if you were thinking the same thing that they were thinking.

They're right.

Sira says, "They don't all have three sides."

This one has one, two, three, four sides.

So that can't be a triangle.

And Tiffany said, "One isn't a closed shape and some sides aren't straight."

And when I look at this I can see this shape right here, it looks like maybe someone was going to try and draw a triangle but they just made three lines and they never really finished it.

So it has three sides but it's called an open shape because the sides aren't touching to make those corners.

Then she says, "Some of the sides aren't straight."

If you look here you can see that there are two straight sides but then this one kind of makes an arc or a little bit of a circle of some sort or a curve in the line.

So that can't be a triangle because a triangle has to have three straight sides.

Great work, Math Mights, on being triangle detectives.

I liked the way that you were able to determine triangles and not triangles.

Now I have some more shapes for us to take a look at.

These are rectangles.

What do you notice?

I notice that some of them are big and some of them are small.

I'm wondering what my friends Sira and Tiffany are noticing.

Sira says, "They all have four sides, "and one is colored in."

And Tiffany says, "I notice a square."

Let's look at the shapes that I have in front of me and you can see that they do all have four sides.

We can count them together.

One, two, three, four.

One, two, three, four.

One, two, three, four.

And this last one.

One, two, three, four.

And Sira did say one of them is colored in.

Even though it's colored in, it can still be a rectangle.

Great noticing, Sira.

And Tiffany said, "I notice a square."

Hmm, I wonder why the square is on this page.

Did you know, Math Mights, that a square is actually a very special kind of rectangle?

So the square can go in the rectangle group.

It has four sides, it actually has four corners, so it can be considered a rectangle.

You can notice that on this top one and on this one these sides are longer than these sides.

Same here, this side is much longer than the side here and here.

And that's what a rectangle is.

I know that we said that a square is a special kind of rectangle, but in most cases on a rectangle the sides are not always the same length.

Two sides are the same length and then the other two sides are the same length.

And one other thing that you can know is that when you are looking at a rectangle there are always four corners.

We said a triangle had three corners and a rectangle has four corners, I'll show you on mine.

And I'm actually gonna use my marker to show you.

I'm gonna circle them.

If you're ever doing this in class then you can always circle the corners so you don't lose track of where you started counting.

You can go like this.

One, two, three, four.

Then you know you have four corners.

Thanks for helping me take a look at the rectangles and dig even deeper to figure out exactly what makes up a rectangle.

What makes these shapes different than the rectangles?

I wonder what you notice when you look at them.

I can see a few different things that make them different than a rectangle.

I wonder what my friends Sira and Tiffany are thinking.

Sira says, "One has an extra side "and one has a line that sticks out."

Tiffany says, "One looks like two rectangles together."

Let's take a look at what I have in front of me because those are really great notices, girls.

We see that Sira said, "One has an extra side."

That's right here.

You can see we have one, two, three, but then she added this little line here, four, five.

So we know that if it has five sides it can't be a rectangle.

When we look down here at the bottom one she said this one has a line that sticks out.

It almost looks like an open shape.

I can see one, two, three sides, but then part of it comes down like this.

This definitely isn't a rectangle.

Then Tiffany said this top shape here looks like it's two rectangles put together, and it does.

I can see I have one, two, three, four, and then I have a line down the middle.

So a rectangle wouldn't have a line through the middle of it, so this one can't be a rectangle either.

Great notices, girls, and great notices, Math Mights.

So far we have looked at triangles and rectangles.

Now it's time for us to look at squares.

What do you notice?

I notice that there are quite a few squares on this paper.

I wonder what my friends Tiffany and Sira are noticing.

Sira says, "I notice they all have four sides "and four corners."

Tiffany says, "I notice there are no rectangles."

Let's take a closer look.

When you see this Sira said they all have four sides and they all have four corners.

We can count them.

One, two, three, four.

One, two, three, four.

One, two, three, four.

One, two, three, four.

She's right, they all have four sides.

We can count the corners on one of them, let's try it.

We have one, two, three, four.

So we know that squares have four sides and four corners.

Tiffany says, "I notice there are no rectangles."

And she's right.

Remember, a square is a special kind of a rectangle, but a rectangle can't ever be a square because rectangles have two sides that are longer than the other two sides.

So great thinking, Tiffany, and great thinking, Sira.

Now Math Mights it's your turn to draw triangles, rectangles, and squares.

I know you're going to do a great job at that.

Great work today, Math Mights.

I had so much fun with you.

We were able to do a number talk with my favorite Math Might, DC, and then we talked about triangles, squares, and rectangles.

Overall I think you did a fantastic job.

I want you to kiss your brains.

(lips smack) Until next time, have a great day.

(bright music) (bright music) - [Child] Sis4teachers.org.

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

- [Announcer] The Michigan Learning Channel is made possible with funding from the Michigan Department of Education, the State of Michigan, and by viewers like you.