(soft music) - [Children] Math Mights!

- Welcome, first grade Math Mights.

I'm Mrs. Markavich, and I'm so excited 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 doing a mystery math mistake, and we'll use 10 to add and subtract.

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

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

D.C. is holding onto Abracus' wand.

What is going on here?

Here's how our mystery math mistake is going to work.

One of our Math Might characters is going to feature a problem they are struggling with.

It's your job to be the detective, and help them find the error, and correctly solve it.

Let's see who needs our help today.

It looks like it's D.C. who needs our help.

D.C. has number bonds to 10, but he's struggling to find the missing add end.

Do you think you can help him find the missing add end?

I know you can.

Let's see what Sunshine thinks.

Sunshine says, when I build 10 on a 10 frame, if I make two red, then I know eight will be yellow.

Let's try that on ours.

I'll go ahead and make the number bond over here with 10, and the two parts.

Now this part has the question mark.

This is that missing add end.

I'm gonna leave it blank, so that I don't have to erase it when we go to fill it in.

But I am going to put the two in.

Now, Sunshine said she's going to make two red on our 10 frame.

And because you're so great at subitizing, like Sunshine, you know that there are eight spaces left on our mat.

Let's count 'em.

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

So our missing add end is eight.

Great thinking, Sunshine.

I'm wondering if you thought the same way that Sunshine thought.

Now I know that D.C. would be so proud of our work, but I think he's struggling with a few more missing add ends.

So let's take a look and see what Mariah thinks.

Mariah says, I know that six and four make 10.

D.C. forgot the four in his number bond.

Mariah told us that D.C. forgot a number, but that the six was there.

So I'm going to build that on mine like this.

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

And because you're such great subitizers, you know that four are left, just like what Mariah said.

Let's fill those in.

One, two, three, and four.

So our missing add end is going to be a four.

Excellent work, ladies.

Now, D.C. has one more number bond for us to work out in order to get him in line, and ready to go.

In our number bond, we have the whole number of 10, and one part is seven, and here is my missing add end, the part I don't know.

I'm going to put seven counters on my 10 frame mat, just like this.

And looking at it, I can see there are one, two, three spaces.

So I know that my missing add end is going to be the number three.

This was really a great discovery to help D.C.

I know that we are becoming great mathematicians when we can find the missing add end, and figure it out when we're helping one of our Math Might friends.

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

It says I can use 10 to help add and subtract.

Let's take a look at this slide.

What do you notice?

What do you wonder?

I'm thinking that I can figure it out without having to count.

Let's see what the girls are thinking.

Sunshine says, I notice there are 13 counters, and 14 connecting cubes.

And Mariah says, there are more connecting cubes than counters.

Both images show one group of 10.

Ooh, these are great notices.

Let's take a closer look.

I've got it blown up nice and big for us here.

Now Sunshine said there were 13 counters, and 14 connecting cubes.

I'm thinking she saw the 10, and counted on 11, 12, and 13.

Over here, she said there were a total of 14, because again, I think she automatically knew this was 10, 11, 12, 13, and 14.

Now sometimes it's helpful if you have place value strips to be able to see this visually.

So I'm going to grab a couple of place value strips, and show you what that looks like.

Here is 10, and the three is hiding that zero to show that 13.

And over here, I have 10, and the four ones are hiding this zero.

Now Mariah says there are more connecting cubes than counters.

And I think she's right.

We can tell, because we can see the 10 here, and a 10 here.

I could easily take that 10 away from both of them, so that you can see, I only have the ones left.

There are only three ones here, but there are four ones here, so she's right.

There are more connecting cubes than there are counters.

And Mariah also said, both groups show an image of 10.

There are 10 counters in the 10 frame, and there are a group of 10 connecting cubes.

These are great mathematical notices.

Let's check out their wonders.

Sunshine is wondering, how many more connecting cubes are there than counters, and Mariah is wondering, how many objects are there altogether?

I definitely think we can figure out their wonders.

Let's try to solve Sunshine's wonder.

She wants to know how many more connecting cubes there are than counters.

So I'm just gonna kind of cover them up.

Here's 10, and here's 10.

So that kind of crosses each other out.

And then I have one, two, three over here that I could cover up, and one, two, three over here.

So now you can see there's only one connecting cube left, so there's one more connecting cube than there are counters.

Great question, Sunshine.

Now Mariah wants to know, how many objects are there altogether?

So I'm going to grab my place value strips again, and we're going to solve this together.

I'm going to start with 10, and then add my ones, which were three ones that gave us 13.

Then for the connecting cubes, I'm going to start with 10, and add the one, two, three, four ones to show the number 14 over here.

Now I bet you're wondering, what am I supposed to do next?

We're going to add the 10s and the ones.

So you can see that I have one, two 10s, which would give us 20.

And then I can add my ones.

One, two, three, four, five, six, seven ones, which will give us the number 27.

This is a great start to our show today.

We're going to continue to talk about using 10 in place value to add and subtract.

Wait a minute, did I hear the word place value?

That means we need to call on him my friend, Value Pak.

Value Pak is a Math Might that lives in Mathville, and he wears his value on his belly.

And he lives in a family where sometimes they work together, so they're clipped together just like this.

And sometimes they can click apart to show their own individual values.

Let's see how Value Pak is going to help us today.

We're going to start by adding teen numbers with Value Pak.

14 equals 10 plus hm, there's that box with that missing add end.

So we're going to go over here, and I'm going to write 14 equals 10 plus that missing part.

Now we're going to start with the number 14.

I just happened to have my place value strips, and Value Pak, who are going to help me.

Here's my number 14.

14 equals 10 plus something.

So what I can do here is I can pull this apart, because sometimes Value Pak clicks apart to show their two individual values.

So when I slide this off, and the four is not hiding the zero anymore, you can see that number 10, which means my other part must be four.

So I know that 10 plus four equals 14, and it's okay that the 14 comes first in this math equation.

Sometimes the answer is on the left side, and not on the right side, and that's just fine.

Let's check out our next expression.

It says 10 plus five equals hm.

So this time I'm looking for the sum.

I'm going to write 10 plus five equals hm.

And I think Value Pak is going to help me, because we're going to pull out the 10, and I'm going to grab my five ones.

Now I can take my five, and I can hide the zero.

I just think this is the coolest trick ever, because it really helps me when I'm adding teen numbers.

I have a 10 plus the five that's hiding the zero, makes the number 15.

So my sum is going to be 15.

Math Mights, we're getting really good at this.

Do you think we could try this a different way?

Do you think we could use Value Pak to help us subtract teen numbers?

I think we can, let's give it a try.

Let's take a look at our first equation.

It says six equals 16 minus hm.

Hmm, that sounds a little confusing.

I think I'm going to draw it out for us, and see if Value Pak can help us solve this one.

All right, let's write the equation.

Six equals 16 minus hm.

I'm going to grab my place value strips, and start with the number 16, because 16 is the greatest number, and then I'm going to subtract hm.

I don't know what I'm subtracting, but on the other side of that equal sign, I can see a six.

So I'm going to pull this apart, and put the six under here, and I can see that I have 10, so it must be 16 minus 10 equals the six.

So I'm going to put the 10 in that empty space.

Let's try another one.

The next one says 15 minus 10 equals hm.

So I'm going to write 15 minus 10 equals hm.

I'm going to start with the 15, which looks like this.

This time, it's asking me to take away the 10, so I can pull this apart, and line the 10 up under here.

I'm taking away the 10, and that's going to leave me with the five.

So 15 minus 10 equals five.

We're really doing a great job, let's try another one.

This one says, hm equals 13 minus three.

I'm going to write that on my board.

Hm equals 13 minus three.

I'm looking for the answer, similar to how I did it right here, but they put the equal sign and the missing part here in the beginning.

So I'm going to say 13, I'm going to grab my place value strips to show the 13.

Then it asks me to take away three.

So I'm going to slide that three over here, and that means I'm left with the 10.

So I'll put the 10 inside of my unknown.

13 minus three equals 10.

Great work, Math Mights.

I think you're getting really good at using the place value strips to add and subtract teen numbers.

Now it's your turn to add and subtract teen numbers with Value Pak.

Great work today, Math Mights, we were able to do a mystery math mistake, and we were able to add and subtract teen numbers with the help from our friend, Value Pak, and his place value strips.

Until I see you next time, kiss your brain.

(soft music) - [Kid] Sis4teachers.org.

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

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

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