(cheerful music) - Math mights.

- Welcome first grade math mights.

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

I have so many great math activities planned for us.

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

Today, we'll be solving a mystery math mistake and we'll add with 3 addends.

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

Oh no.

All of our math mights have gotten their strategies all mixed up.

DC is holding Abracus's wand.

What is going on here?

Okay.

So here's how the mystery math mistake is going to work.

One of our math might characters will be featuring a problem that they're struggling with.

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

Let's see who needs our help today.

It looks like Value Pak needs our help.

I think Value Pak is decomposing teen numbers, but it looks like he forgot one of the numbers.

Do you think you can help Value Pak?

Do you see some of the errors?

Let's see what our friend Landon is thinking.

Landon says, "When I build 18 on my place value strips, it decomposes into 10 and 8 because, 10 + 8 = 18."

Hmm.

I think we need to check this out.

Let's take a look at it together on mine.

I have a double 10 frame mat, the number bond and the place value strips.

So you can see here on the number bond we have the number 18, 10, and that missing part.

Now Landon said, "When I build the number 18, I know that it is 10 and 8."

So remember Value Pak can click apart to show his own individual values.

So let's pull that 18 apart like this.

Now you can see the two parts that Landon was talking about.

10 and 8.

We can also build that on our double 10 frame mat.

Let's put the 10 on top.

And that means we'll fill that whole 10 frame like this there's 5, 6, 7, 8, 9, and 10 .

There's that part that we knew.

Now, here's that part that was missing in the number bond.

So let's put that 8 in the bottom of the double 10 frame.

We'll use yellow this time.

1, 2, 3, 4, 5, 6, 7 and 8.

There are our two parts.

Let's go back over to our number bond and add that missing part, that was 8.

That was great help from Landon.

And I think that Value Pak would be so proud of our help, but I think there are a few more number bonds that Value Pak needs help with.

Let's see what Ryan's thinking.

Ryan says, "I know when I decomposed 16 with my place value strips, it is 10 + 6 = 16.

I like the way that Ryan is thinking.

Let's take a closer look at it on mine.

All right.

So once again, I have the double 10 frame map, the number bond with the missing part and the place value strips that show the number 16.

Now, Ryan said he knew that 10 + 6 = 16.

So what I want to do is click that number apart like Value Pak does to show the two individual values.

Let's do that now.

When we pull it apart, there's what Ryan was talking about.

10 and 6 equal that number 16.

We can go ahead and build that on our double 10 frame mat.

Let's do that now.

We'll put the 10 on top and the 6 on the bottom.

We'll show the 10 in red.

1, 2, 3, 4, 5, 6, 7, 8, 9, and 10.

And then our other part, which is 6.

1, 2, 3, 4, 5 and 6.

Now, when we look at our two numbers, we can see the 6, which is shown on the bottom is already in our number bond.

So that just means the last thing we need to add is the 10, like this.

Now we can see that our number bond is fixed.

I know Value Pak appreciates our help, but we have one more number bond to help set him straight.

Let's take a look at that one.

This time, our number bond reads 15 and then, and 5.

Let's take a look at mine and see if we can solve this together.

I've started our double 10 frame mat with that number 15 in there.

Then you can see we have the missing part and the 5.

I laid out our place value strips right here.

I'm going to go ahead and decompose that 15 or pull it apart, how Value Pak likes to click apart to show the two individual values.

Let's do that first.

So now when I look at this, I can see the two parts of 15 are 10 and 5, and there's a 5 in my number bond.

I'm going to go over to my double 10 frame mat and show you that 5 and see if you can see the 10.

So we're going to turn these over, 1, 2, 3, 4, and 5.

There's our 5.

And here is our full 10 frame at the top that has 10 counters in it.

So we can go over to our number bond and add that 10.

This is a great discovery for helping Value Pak.

First grade math mights, you know, you're becoming mathematicians when you can find errors in math and solve them correctly.

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

It says, "I can find sums with 3 addends."

Let's take a look at this.

How many do you see?

How do you see them?

I see some 10 frames that look familiar, but this time I see 3 colors.

I see red, yellow and blue.

Let's see what the boys are thinking.

The boys are telling us how many they see and how they see them.

Landon says 15.

I see a full 10 frame and 5 more.

Ryan says 16.

I see 5 and 5 is 10 and 6 more is 16.

I really liked the way that the boys are communicating what they saw and how they saw it.

Let's take a closer look on mine.

We'll start with Landon's.

Landon says, "I saw a full 10 frame right here of 10 and 5 more."

So we could write this like this, 10 + 5 = 15.

And then Ryan said, "I saw 5 and 5, which make 10."

So we can write, 10 + 6 = 16.

Now there's one more way that we could write the way that Ryan was telling us.

We could break it down to show the 3 addends.

Let's do that now.

You can see that there were 5 red plus 5 yellow plus the 6 blue equals 16.

Now you can clearly see that we are adding 3 addends, but what about that last 10 frame?

Let's take a look at it together so that we can solve it.

I have 4 red, plus 6 yellow, and I can see that that 10 frame is full.

So that would give me 10, but I'm not going to write it.

I'm going to put another plus sign and then add the blue ones.

4 plus 6, plus the 8 blue, gives me a total of 18.

Now let's take a look at this.

We have a 3 addend dilemma.

Landon thinks it's easier to add 8 and 5 on the 10 frame first, then add in the 2.

Do you agree or disagree?

I think we need to take a closer look at this.

I've laid them out in front of me here.

8, 5 and 2.

He thinks we need to add the 8 and the 5 first.

So I'm thinking in first grade, what my students would do is they would say 1, 2, 3, 4, 5, 6, 7, 8.

Well, that's not very efficient.

We're getting really good at subitizing.

So what we need to do is use what we know about subitizing to be more efficient when we're adding 3 addends.

Ryan says, "I politely disagree.

I think it would be easier to add the 8 and the 2 to make a 10."

This makes a lot of sense to me.

If you take a look at mine, you can see that Ryan says we should add the 8 and the 2 to make a 10.

Now, if I kind of snuck that over, just like that, you would be able to see, I have a full 10 frame here.

Then I could say, 10, 11, 12, 13, 14, 15.

I could just count on.

That was a really efficient way to add the 3 addends.

Now let's play a game called, Deck o' Dots: 3 Addend Duel.

Here's how it works.

You're going to draw 3 Deck o' Dot cards.

The goal is to find the most efficient way to add the 3 addends.

The person with the highest total or sum, wins all of the cards and their partners cards.

I have DC and Value Pak here to play a few rounds with me.

Let's see how they do.

DC is going to draw first.

DC is drawing a 7, another 7 and 3.

Now, it wouldn't be very efficient to add the 7 and the 7.

We already know that number would be larger than 10.

I think DC is going to add the 7 and the 3 to make a 10 and then add 7 more and that would give him the total of 17, like this.

Now it's Value Pak's turn to draw.

Value Pak drew a one, a nine and a five.

Are you thinking what I'm thinking?

I'm thinking that Value Pak is going to put the 1 and the 9 together to make a 10.

You can see that space right there.

Then add the 5 to give him the total of 15.

Now, when we look at the two answers, who has the larger sum, DC or Value Pak?

DC does, so he wins all of the Deck o' Dot cards.

Let's play one more round.

We're getting really good at this.

It's DC's turn again because he won the cards.

DC draws a six, a four and a three Do you think that DC is going to add the 6 and the 3, or the 6 and the 4?

I think you're really good at subitizing, so I think, you know, he's going to add the 6 and the 4 to make 10, and then add the 3 more to make the number 13.

I'm going to record that number right here.

Now it's Value Pak's turn.

Value Pak draws an eight, a two and a six.

I can see Value Pak really thinking, but I think he knows that he needs to add the 8 and the 2 to make a 10 and then add 6 more, which will give Value Pak the total of 16.

We'll record that right here.

Now, when we compare the two totals, DC had 13, Value Pak had 16.

So it looks like Value Pak wins this time.

Value Pak gets to keep all of those cards.

It looks like we have a tie.

So we're going to need to do a tie breaker.

Here's how it's going to work.

I'm going to put out 3 Deck o' Dot cards.

Whoever can make the 10, the fastest and give me the total is going to be the winner.

Let's see whose brain is working quickly.

Our three cards are 8, 5 and 5.

Oh, I see that DC says, "I know it, I know it.

5 and 5, make a 10 and then 8 more make 18.

Value Pak looks a little confused.

Value Pak was going like this 8, 9, 10, 11, 12... Oh, oh, I think Value Pak needs a little more practice with this.

Remember, it's super important to be able to subitize and make a 10, and then you can add much more efficiently.

Now it's your turn to play Deck o' Dots: 3 Addend Duel.

And don't forget the person with the most cards at the end is the winner of the game.

Great work today, math mights, we were able to solve a mystery math mistake and add with 3 addends.

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

(cheerful music) - [Child] Sis4teachers.org, changing the way you think about math.

- [Woman] The Michigan learning channel is made possible with funding from the Michigan department of education, the state of Michigan and by viewers like you.

(cheerful music)