(jolly music) (bells and chimes) - [Children] Math Mights.

- Welcome, first grade Math Mights.

I'm Mrs. Markavich, and I'm so excited that you're here with me today.

I have so many great math activities planned for us that I know you're going to love.

Speaking of math activities, let's check out our plan for the day.

Today, we'll solve a mystery math mistake and we'll make a 10.

Let's warm up our math brains with a mystery math mistake.

Oh, no, all of our Math Might friends have gotten their strategies all mixed up.

DC is holding Abacuses' wand.

What is going on here?

Here's how the mystery math mistake works.

One of our Math Might friends is going to be featuring a problem that they're struggling with.

It's your job to find the mistake and help them solve it correctly.

Let's see who needs our help today.

It looks like Value Pak needs our help.

Value Pak is trying to add nine plus 10 equals nine plus 10 plus one.

Hmm.

I wonder how he needs help.

I think we need to call on my friend, Landon.

Landon says, "I think Value Pak is confused.

I know when I add nine plus 10, it equals 19."

Oh, I think we need to take a closer look at this on mine.

I've gotten it all written out right here for us, and I have the 10 frames laid out with nine, 10, and one, because those are all of the numbers in our problem.

Now, Landon said, "I know nine plus 10 equals the number 19."

And I have that right here.

See?

There's where Value Pak starts.

Actually, I'll switch them around like this, with the nine and the 10, but then that nine hides that zero and we get the number 19.

So he must have added nine plus 10.

I'm gonna move that aside and put the total, 19, right here.

Now, I understand what Landon is saying.

Nine plus 10 does equal 19, but I still think I'm a little confused.

What about the other half of the problem?

Let's see what our friend Ryan is thinking.

Ryan says, "If you add nine plus one, it equals 10, then add in 10, It will be 20, which is not the same as nine plus 10 equals 19."

Hmm.

That sounded like a lot.

We better take a closer look at that.

So the first thing that Ryan said was if you add nine and one, so you can see where that one fits right in there to make a 10, it would equal 10.

And then I'm just gonna kind of put this like that.

And then he said, "10 plus 10 equals 20."

So I'm going to write a 20 over here.

And then he said, "That is not the same as nine plus 10 equals 19."

He is right.

When we're looking at this kind of an equation, the left side has to be the same as the right side in order for it to be equal.

And in this case, 19 is not the same as 20, so this is not equal.

First grade Math Mights, you know you're becoming mathematicians when you're able to find errors in math and solve them correctly.

Now, let's check out our I can statement of the day.

It says, "I can make a 10 to help me add."

Let's take a look at this slide.

How many do you see?

How do you see them?

Hmm, well, I see some double 10 frames, but they're not all the way filled in, so that makes it a little hard for me to figure out the total.

I wonder what the boys are thinking.

I think they are telling me how many they see and how they see them.

Landon says, "10.

I took one from the bottom and added it to nine.

So nine and one is 10."

And Ryan says, "15.

I took one from the sixth and added it to the nine to make 10.

So 10 and five is 15."

Wow, that seems like a lot of information.

I think we need to break it down and talk about Landon's first.

So let's take a look at mine.

Landon said, "I took one from the bottom and put it up top to make 10."

So I have that right here.

You can see nine and you can see that empty space where we could fit one more, so we're gonna go ahead and move that in there, just like Landon said.

Now he sees 10.

Great thinking, Landon.

Now, let's talk about the way that Ryan saw it.

So Ryan said, "15."

I took one from the bottom and moved it to the top and made a 10, and he knows 10 and five make 15.

This is great thinking by both of the boys, they were using what they know about subitizing to make a 10, but wait a minute, we have one more 10 frame to take a look at.

Let's solve that together.

The bottom one here has seven on top and eight on the bottom, so I'm going to quickly build that on mine, just like this.

I have seven on top and eight on the bottom.

Now, I bet you're thinking, "I already know how to make a 10."

Let me see.

Were you going to take the three from the bottom and move them up to the top to make 10?

If so, you're right.

Let's move those three up, just like this.

Now we have 10 and five, which makes 15.

This is great work for what we're going to be doing today, which is making 10, and I have a Math Might friend who is going to be able to help us.

Let's see who it is.

(gentle music) Oh, hey, it's my friend DC.

DC is a Math Might that lives in Mathville.

He wears a hard hat and has a mallet.

DC likes friendly numbers, and if he doesn't see a friendly number, he gets really angry and he smashes that number with his mallet to turn it into a friendly number.

Let's see what DC has set up for us now.

It looks like DC wants us to make a 10 to help solve the problem eight plus five.

And you can see the 10 frames that have eight and five in them.

Let's see what my first friend thinks.

Landon says, "I used the double 10 frame and decomposed the five into two and three, then I added the two with the eight to make a 10, then I added 10 plus three, which equals 13."

Landon sure had a lot to say about this problem.

I think we need to head over and take a closer look at it.

So what I have here is eight and five.

Now, Landon said he decomposed the five into two and three.

Why do you think he did that?

I think this is a great visual for us to see.

You can see that these two are going to go right up here to make that 10, and then the three, which would give us 13.

Now, since you did such a great job of sliding the two up and making that 10, let's go ahead and write out the problem so you can see it another way.

I have eight plus five.

Now, here is where DC helped us decompose the five into two and three.

Then, I'm gonna take the two and the eight and grab them together, where I've got eight and two, and that gives us the 10 plus the three, which gives us the total, I could slide this over, of 13.

Now, do you think this is the only way that we could solve this problem?

Is the five the only number that we could decompose?

Well, let's see what my friend Ryan is thinking.

Ryan says, "I see another way we can solve it.

I decomposed the eight into three and five, then I added five and five to get 10.

Last, I did three plus 10 equals 13."

Wow.

This sounds like a great idea.

I think we should check this out on my whiteboard.

So Ryan says he decomposed the eight into five and three.

So I'll do that just like this.

I'll flip the top five over.

Then, what you're going to do is take those five, because he said five and five make 10.

So we'll move them down into that bottom 10 frame, just like this.

Now you can see 10 and three make 13.

Now, if we were to write this problem out, it would look like this, eight plus five.

He decomposed the eight into three and five.

Now we know that five and five make 10, plus three more give us the total of 13.

Wow, this was really great work of using what you know about subitizing and decomposing numbers to make a 10.

I think it was so helpful of DC.

He must be so proud of us.

Let's see if we can make a 10 using another tool.

Let's try making a 10 with my counting buddy Senior.

We'll try to solve the problem, nine plus six equals hmm.

Before we do that, let's do a quick review of the Counting buddy Senior.

Here he is now.

Remember, he has a head and feet.

The Counting buddy Senior has 20 beads on it.

On this one, 10 of them are yellow and 10 of them are orange.

So let's get started with our problem.

We have nine plus six equals hmm.

So let's pull down nine yellow beads.

One, two, three, four, five, six, seven, eight, and nine.

Now, we need to add six.

Let's pull down six beads.

One, two, three, four, five, and six.

Are you seeing what I'm seeing?

Do you think you know how to decompose the six so that we can make a 10?

I think you're right.

Let's take the six and look at the beads.

Right here, I have one yellow and five orange.

Now, what I can do is have this one and nine grabbed together.

So I'll slide this yellow bead over.

That gives us 10, and then we have five over here, and we know that 10 add five is 15, so we can write that answer next to the expression of 15.

That was great work.

This time, we're going to try it again with another problem, six plus eight equals hmm, but this time I've put the smaller number first.

Do you think you can do it?

I know you can.

Let's take a look and get some help from the Counting buddy Senior.

So we're going to start by building the six, one, two, three, four, five, six, then we need to add eight.

I'll slide eight over.

One, two, three, four, five, six, seven, eight.

Are you getting the idea?

Are you seeing what I'm seeing?

We've got the six and then you can see the two parts of eight.

So we're going to decompose the eight into four and four.

Now, we're gonna lasso that four in from the six, just like this, and I'll slide those four over.

This gives us a 10, and four more would give us the total of 14.

So let's go ahead and write that over here.

Now that we've used the Counting buddy Senior, I wanna take that same problem and see if we can use DC's strategy of the double 10 frame.

Let's give it a try.

I've built the problem for us, six plus eight.

Now, remember we decompose the eight into four and four, so you can see the four spaces across the top where I need to move some counters.

So I'm going to move one, two, three, four counters up here.

Now I have that 10, that was six and four, plus the four on the bottom, and that's gonna give me the total of 14.

Math Mights, DC would be jumping with joy that we were able to use his strategies in more than one way with multiple tools.

I think you should be so proud of yourselves.

Now it's your turn to make a 10 with DC.

First grade Math Mights, I had so much fun with you today.

We were able to solve a mystery math mistake and help my friend Value Pak, and then we were able to get some help from my friend, DC, to make a 10.

Until I see you next time, I want you to kiss your brain.

(gentle music) (jolly music) - [Boy] Sis4teachers.org.

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

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

(gentle music continues)