(whimsical music) - Well, hello there third graders.

My name is Mrs. Ignagni and I am back for an exciting episode of Math Mights.

Let's take a look at our plan for today.

We are going to warm up our math brains with a mystery math mistake.

Then we are going to add within 1000.

Whoa!

What's happening to our mathville characters?

It looks like their strategies are all mixed up from being stuck in a cyclone.

Well, third graders, this is how a math mystery works.

One of our MathVille characters is going to show us a problem that they have been struggling with.

It is our job to look closely at that problem and figure out what went wrong, so that we can help our math character find the correct answer to the problem.

I wonder though, which one of our MathVille characters is going to need help today.

It looks like Value Pak is all upside down and need our help.

Value Pak is trying to add 143 + 256.

However, when he is decomposing into that place value, it looks like something might have gone wrong.

If I have our problem, 143 + 256, if I decompose by place value, I know that 143 is going to break into my 100, my 40, my 4 tens and 3 ones.

Value Pak decomposed 256 into 200, 40, and his 6 ones to get 256.

Now I'm going to show you how Value Pak used partial sums to solve that.

Using our strategy of partial sums, I can go ahead and start with adding my 100 and my 200 to get 300 just like Value Pak did, now adding my tens, 40 plus 40 equals 80, and my ones 3 + 6 equals 9.

Now I just have to add those three together to get 389.

What do you think boys and girls, did you see a mystery math mistake?

I wonder what the girls noticed.

Sunshine said, "It looks like Value Pak decomposed the first addend by place value correctly, but not the second number."

When I looked closer at this, I can see what sunshine is saying.

It does look like that Value Pak was able to break down that first number correctly, but it looks like there might be something wrong on our second addend.

Let's see what our friend Mira thinks.

Mira said 256 equals 200 + 50 + 6, not 200 + 40 + 6.

Therefore the answer is incorrect and needs to be corrected.

Looking at our second addend.

I see what she's saying and I see our mistake.

It needs to be 200 + 50 with 6 ones.

So now when I go back to adding those together, I have to make that correction.

I have, my hundreds are the same 100 and 200 does equal 300, but now that I have 40 plus a 50, that's going to equal 90.

My ones are okay, so I'm going to keep those the same.

And now I know that my correct answer is 399.

Nice work boys and girls.

For third graders, being able to look at a problem that was solved incorrectly, but to actually dive deeper into it and be able to solve it correctly.

Sure is tough work.

Great job.

Let's go ahead and take a look at our, "I can" statement of the day.

Our "I can" statement of the day is, I can use strategies to add within 1000.

If we're going to be adding within 1000, we should find out a way to show off all those math strategies using a game called 'Math Mights ShowDown: Addition Strategies.'

This is how this game works.

You need your Math Mights Showdown: Addition Strategies game board, and some counters.

With my Math Mights ShowDown game board, I'm going to be practicing my three digit by three digit numbers with a friend.

Now, in this case, we are going to have sunshine BR yellow counter, and we're going to have Mira BR red counter.

Now the goal of the game is to pick a equation to show off one of the strategies that you've learned.

You can use either DC strategy of decomposing and composing numbers.

You can use Abracus's strategy of compensation or working with a Value Pak, you can use the strategy of partial sums, but the goal of the game is to strategically pick which equation you're going to solve so that you can get four in a row before your partner does.

Are you ready to try this out?

Sunshine is up first.

And she said, "I am going to do 298 + 152 using compensation with Abracus."

So looking at her game board, sunshine is going to choose to solve the equation 298 + 152 using Abracus.

You remember our good friend Abracus.

He is our most magical character in MathVille, and he loves dealing with the strategy of compensation.

Abracus uses that magic wand of his to zap numbers into a more friendlier form, so that he can easily add those numbers as opposed to the first equation he started off with.

But Abracus always has to remember that he needs to make sure he zaps whatever number back, so that the equation is correct and make sense.

Let's see how Abracus would solve this.

To make this a little bit more friendlier to work with, Abracus is actually going to zap this 298 into 300, by adding two to our original number.

Then he's going to look over here and he could add 300 to 152, but if he actually zaps this one to 150, he now has a nice, simple equation, 300 + 150 equals 450.

Now in this case with Abracus because he zapped on two and then he automatically zapped two off with the other addend, it's okay, because he was able to zap correctly.

So it makes sense.

Abracus would be so proud of sunshine because she went ahead and solved that equation correctly, using his strategy.

Now in the Math Mights ShowDown game, it's important that your partner checks your work to make sure that you actually use that strategy correctly and should be able to put that counter on there.

So Mira did tell me that she agrees sunshine used compensation correctly.

Mira said, "I am going to do 128 + 217 using decomposing/composing with DC."

Looking at our game board.

It looks like Mira has decided to work on this equation and she's using our good friend DC to decompose that problem.

Now remember our friend DC lives in MathVille and he loves decomposing numbers, and he wears that hard hat and carries that mallet because when he comes across an unfriendly number, he uses that mallet to make it into a more friendly number so that he can easily add with it.

Let's see how Mira is going to use DC strategy.

So using DC strategy, Mira broke 217 into two and 215, so that she could easily make this friendly number of 130.

Then she could easily add 215 to get her total of 345.

Well, when sunshine checked her work, she agreed Mira did come up with the correct answer.

So we're going to go ahead and put our counter there to show that Mira correctly solved that three digit equation using that strategy correctly.

Next up, it's Sunshine's turn again.

And it has to be a little bit strategic this time, because remember the goal of this game is to get four in a row.

So looking at where she's at, she has already solved this square correctly.

So she could either choose to go up this way and choose this equation.

Or she could go to the side to solve for this equation or boys and girls, she could even go diagonally in this game and in this particular case, and she's here, she could solve for this equation.

The goal of the game though, is that she decides that based on that strategy that she wants to show.

Let's see what sunshine decided.

Sunshine said, "I am going to do 524 + 118 using partial sums with Value Pak."

Looking at our game board, sunshine has decided to go up and solve this equation, using our friend Value Pak.

Now you remember Value Pak from MathVille.

This is our family that likes to travel together and loves working with partial sums.

Together you'll see that they make the number 27, but when our family separates, our red character has a 20 on his belly to represent that tens column, While our white character has a seven on his belly to represent the ones.

Let's see how sunshine uses Value Pak strategy to solve this equation.

So looking at our first addend, sunshine is going to go ahead and break 524 and decompose that by place value, and she's actually going to have three numbers.

She's going to have 500, 20 and 4.

Sunshine's going to go ahead and do the same thing with that second addend and decompose it into place value.

So if we have 118, it's actually going to become a 100, 10 and 8.

From there, we're going to go ahead and utilize our strategy of partial sums to add those hundreds, tens and ones together, to get our full answer.

If we have 500 + 100 that would equal 600, 20 plus 10 equals 30, and then 4 + 8 equals 12.

Now, all we have to do is add those numbers together to get our final equation answer.

If we have 600 + 30 + 12, we have 642.

Excellent work sunshine showing that strategy of Value Pak.

So checking her work, Mira agrees with sunshine that she did in fact use the value pack strategy correctly.

So we're going to go ahead and place that counter to show that she in fact has two in a row.

Sunshine is on her way to winning this game, having two when she only needs two more to get that four in a row, but it's Mira's turn, let's see if she is going to use the same strategy, or if she's going to use a different one.

Speaking with Mira, now that it's her turn, she told me that she wants to be strategic.

Now, instead of trying to go for four in a row, she's actually going to try to block sunshine because she's a little bit nervous that sunshine already has two in a row.

So with that in mind, Mira is actually going to try this equation.

She's going to use Abracus's strategy to solve 249 + 149 with the hopes of blocking sunshine.

So Mira is using Abracus's strategy of compensation.

And what she's actually going to do is she is going to take this 249, and she's going to zap it into 250 by adding one.

Then she's going to come over here to 149 and she's going to do the same thing.

She's going to zap that into 150 by adding one to it, to get 150.

Now she's going to combine those two totals and she's going to see that 250 + 150 equals 400.

Now, remember since Mira zapped two onto that problem to make it a little bit more friendlier, she needs to remember now to zap two off.

So if she has 400 to take away two, she now has 398, which is that correct answer.

398, nice work Mira.

But remember we have to see if sunshine agrees, sunshine did check Mira's work, and she agrees that she did use that strategy correctly to solve for this equation.

So she goes ahead and puts her counter there.

But remember boys and girls, a key component to this game is that there has to be an agreement.

If for whatever reason after looking at that problem, sunshine did not agree with Mira, or if you're playing and your partner doesn't agree with you, then you both need to work together to solve out that problem, to see who in fact is correct.

If you find out that you were incorrect or in this case, if sunshine realized that mira was incorrect and they solved it together, then Mira wouldn't be able to put her counter there.

But in this case, they came to an agreement.

So now we can see that sunshine is blocked here because Mira was successful in solving that equation.

Now, sunshine has two choices to make.

Where is she going to go next?

And which way?

Could she still continue and go diagonal to get four in a row?

Or she could choose to go sideways to get four in a row.

The girls would go ahead and keep playing this game.

Taking turns, checking each other's work until they got four in a row to see who is the winner.

But now it's your turn to play the Math Might ShowDown: Addition Strategies, just like we did today.

You're going to use those three different strategies to solve your problems with a friend.

Excellent work today, third graders, you were able to show how you can use multiple strategies to add within 1000.

I can't wait to see what you do next time, but until then, bye.

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