(upbeat music) - [Children] Math Mights.

- Hi, kindergarten Math Mights, thanks for joining me.

My name is Mrs. Gray, and I can't wait to do math with you today.

Today, we are going to be doing a mystery math mistake and we're going to be representing numbers 11 through 19 in different ways.

Take a look at the Math Mights.

Oh my goodness they're all mixed up, they have gotten all of their math strategies confused.

What we're going to do is I'm gonna be showing you a problem, and I'm gonna show you how our friend D.C solved the problem as I do it I want you to be using your magnifying glass and really paying attention and taking a close look at how I do it.

You are gonna be on the lookout for a mystery math mistake and if you see it, you're gonna have to help me fix it so that we can go forward and do math the right way.

Our friend D.C. had some different number bonds and in these number bonds, there was a number missing, it is called a missing adamant, and what it is, is one of the parts is missing that would come together to make the total.

Now, here is how D.C. solved it.

D.C. said, that if we had five and a number to make eight that number would have to be three.

He thought five and three made eight.

Then he did it a different way, so there was a number and six, that when put together made eight.

D.C. said that that number had to be three, three and six, make eight.

And on the last one he had seven and a number that would make eight.

He said that that number would have to be one, seven and one make eight.

What do you think?

How did D.C. do?

Did he do them all right?

Or did he make a mystery math mistake?

Let's take a look at what our friends, Nora and Laila saw.

Nora said that two of the number bonds were correct, they had the correct missing part.

And our friend Laila, said she thought that the number bond with six plus hmm equaled eight needed to be changed, because D.C. put three and six plus three equals nine, not eight it needs to be six and two.

Let's take a closer look.

So our friend Laila said that this must be the wrong one because if we had three plus six that would equal nine, I think she's right.

Six and three together makes nine.

Let's get rid of that and try again.

So, Laila said that the three needs to be changed to be the number two.

Because, two plus six equals eight and when we have two and six, that would equal eight.

I think D.C needs to be turned around because we were able to find his mystery math mistake.

Did you find it?

Now let's look at that I can statement for today.

I can represent numbers 11 through 19 in more than one way.

Take a look at this picture.

How many beads do you see?

How do you know?

Let's hear from our friend our friend Nora said that she saw seven because she saw five beads and a group of two beads.

Let's go back to the picture there it is.

She saw five red and two blue that's how she got seven.

Our friend Laila, said that she saw seven because she saw three left and she knew that there was 10 beads on the top, so if three were left, that means there were seven let's go back to the picture.

Here it is, I see on the top row, there are three blue beads all the way to the right hand side that means we're not using those.

So there was seven because there was three leftover if there was 10 total.

What is this?

This is a new tool.

Do you know what the tool is?

The tool is called a rekenrek, let's look at it.

What it is, is rows of beads.

There are, 10 beads on the top and 10 beads on the bottom.

For the 10 on the top five are in one color and five are in another color.

We kind of use this tool like we did our counting buddy.

Do you remember using our accounting buddy?

Anytime the beads were up by the head that means we don't actually count them.

So let's look, on my rekenrek I have a happy face that's to the right.

White goes to the right, white, right and when it's on the right, we don't actually count those beads we pretend that they're not there.

If I want to count the beads I have to slide them over to the left-hand side.

Lemme build a number for you.

So if I built five and three this rekenrek shows the number eight because there's five and three.

Remember, the beads on this side we pretend are not there let's try another number.

I could slide over 10 and maybe two more.

This is 10 and two, this is the number 12.

We could also use our place value strips to help show the number 12.

So I could show 10 and I could show two.

And when I click them together, this is the number 12 just like on our rekenrek.

So now let's clear our rekenrek remember, white goes to the right, and that means it's clear.

So I'll build 10 and maybe six.

We can use our place value strips to show 10 and six.

When we click it together, this is 16, 10 and six more is 16.

Wow Math Mights you're working so hard for me today.

Now take a look at the picture I have here of a rekenrek.

How many beads are on the top row?

How many beads are on the bottom row?

How many beads are there in all?

Let's take a closer look as I build it on the rekenrek.

So we saw this in our picture.

There were 10 beads on the top row I know there's 10 because there's no more leftover and five and five makes 10.

On the bottom row, there is two beads, that means if I had 10 and two, there is 12.

Now, let's try to take what we just did on the rekenrek and we're going to show it, on a double 10 frame mat.

How can this tool be used?

These tools are very similar.

They each show, a group of 10 and this one also shows a group of 10 but they're also very different on the double 10 frame mat the number is shown as stacked that means that there is five up here and five underneath to show the 10 and under that there is five and five under that to show the 10.

When we go over to the rekenrek, this is called linear that means that the five and five are next to each other and same thing if I pushed them back together on this row, five and five.

Let's go back to what we had with the 12.

We're gonna try and show that 12 on our double 10 frame mat.

So on the rekenrek there was 10 on the top.

Well, I know on my 10 frame mat, a 10 frame has 10 boxes so, we're gonna be putting one chip in each box.

I don't even need to count because I know there's 10 you can't add more and you can't take any boxes away so there has to be 10.

If each box had 10, that would match the top row on our rekenrek.

The bottom row has two so that means on our double 10 frame, I'm gonna put two on the bottom 10 frame.

Both tools show the number 12, this tool shows 10 and two more.

And this tool also shows 10 and two more just in a little bit of a different way but they both show the number 12.

Now we can use our place value strips.

The number 12 can be seen as 10 just like on here and up here and two, like here and here.

And when we click them together, that's the number 12.

Wow Math Mights you did such a great job helping me show that number on two different tools.

Now I think you're ready for a challenge.

We're gonna try it again but this time we're gonna show a number on three different tools.

Are you up for the challenge?

So we are gonna be showing the number 14 and we're gonna be showing the number 14 on the rekenrek, the counting buddy and the double 10 frame.

So the first thing we're gonna do is we're gonna look closely at our place value strips.

So if I look close at 14, I could break that apart and see that 14 is actually 10 and four.

Hey, that's the 10 way, can you say it?

Say 10 and four, that would make 14.

So I'm gonna click them back together to show 14.

Now let's go to our rekenrek.

I'm gonna build the 10 and then the four.

So we're gonna take all the beads on the top row and slide them over, that would show the 10.

Then I'm gonna take four beads and slide them over that would be the four.

Let's try the counting buddy next.

So we're gonna take our counting buddy, we're gonna start with the 10 So I'm gonna slide over 10 beads and you know what?

I don't even need to count them because I know there are 10 beads of one color so when I slide over all of the pink beads, that's 10 then I'm gonna slide over four more one, two, three, four, 10 and four is 14.

How are you doing?

Are you ready to try the double 10 frame?

I'm gonna build the ten first, there's my 10.

Now I have to build the four more one, two, three, four, 10 and four more, is 14.

Wow Math Mights look at all three of our tools.

Each tool shows 10 and four but each tool shows it a little differently.

Great job Math Mights that was so fun being able to represent a number on three different tools.

Now you're gonna get to play a game called cover up.

This is a game that you can play with a partner.

What you're going to do is, you are going to have a stack of cards that have a number on them and each of you are going to have a game board.

You are gonna take turns, flipping a card to see a number.

After you flip over the card you're going to match it onto your game board.

The game board shows the number, but it shows it either on a double 10 frame or, on a picture like a rekenrek.

And you go back and forth and take turns until you have covered up every picture on your game board.

You have worked so hard today we did the mystery math mistake and we represented the numbers 11 through 19 in so many different ways.

I hope that you had a great time with me and I can't wait for you to come back soon.