[bright music] - Hello, my name is Ms. Tahese.

I'm a first grade teacher and today I'm going to show you two strategies that we can use when we're adding numbers or subtracting numbers within the number 20.

The first strategy is called make a 10.

And that is what we're going to use when we're adding numbers.

The second strategy is called take from 10 and that's a strategy that we'll use when we're subtracting numbers within 20.

Now in my classroom, my students really enjoy playing with baby dolls and learning about baby animals and it's just babies everywhere.

So what I wanted to do is because they have such an interest in babies, I wanted to extend that interest to math.

And so what I did is I took some counters, the red and yellow counters that we have in our classroom, and I just added little images of babies to it.

Then I made these two mats.

Well, they're double-sided and I'll show you each side.

So this side is gonna be the side that we use for our make a 10.

And as you can see, there are two 10 frames.

There are two places for spinning, that's gonna give us the number we need, and a place to write our number sentence.

Now today when we play our game or do the activity, we are gonna pretend that the 10 frames are cribs since we're working with babies and we wanna put the babies in the cribs to go to sleep.

So that's what we're gonna do when we do our make a 10 game.

When we do our take from 10 game, again, now if you see I have again another two 10 frames, two more spinners with numbers that go up to 14, and then a place to write our number sentences.

In this game, we're gonna pretend that the babies are in the crib sleeping but some of them get up and are hungry and are taken out of the crib to have a snack and we're gonna find out how many babies are left napping.

In order to play both games, whether it's the make a 10 or take from 10, we are gonna need some other items besides our counters.

We are going to need a paper clip and a pencil.

This is gonna serve as our spinner.

So simply we would just put our paperclip here where the black dot is, use our pencil to hold it in place and spin to get our numbers for our number sentence.

Today I'm here with... - Lily!

- Thanks Lily for joining me.

So we are going to start our first activity.

Like I said in the beginning, we are going to do an activity where we're going to make a 10 using the numbers within 20.

So Lily's gonna go ahead and start by spinning on her wheel for her first number.

- Seven.

- Seven.

So we're gonna go ahead and write seven into our number sentence so that we don't forget.

And then Lily's gonna go ahead and add those babies to the crib.

Go ahead, Lily.

- I'm gonna put five in the top.

'Cause I know that five is half of 10, so it probably would be five in the top.

And I count on.

Six, seven.

- Awesome.

Now Lily's gonna spin to see how many babies need to go into our second crib.

- Four.

- Four, awesome.

Let's add some babies to that second crib.

- And I'll just put one less from the top, from the full one because I know that it's five.

- Some of us already know what seven plus four is, but instead of just knowing it, right, we can come up with a strategy.

And like we said, our strategy today is make a 10.

So Lily is gonna show us now how we would make a 10.

So Lily, if we wanna make a 10, how many babies are we gonna take from our second crib and put 'em into the top crib?

- Three.

- Three.

Okay.

And so now Lily, what would be our new number sentence starting with our top crib?

- It would be 10 plus one.

- Great.

And what does 10 plus one give us?

- 11.

- 11.

So that means if 10 plus one is 11, then seven plus four must be... - 11.

- Right, because we didn't get rid of any babies, right?

And we didn't add any more.

We're still the same amount.

We just moved the way that they are in the crib.

So now that we've done our make a 10, we're going to do another strategy, our take from 10.

And this again, like I said in the beginning, is what we use when we're subtracting numbers within 20.

So we are going to flip our boards over because as I told you, we have it on both sides.

Okay.

And we are going to get started.

So Lily's gonna spin.

- 12.

- 12.

- Fill up one of a 10 frame because it's a 10 frame, you know that there's going to be 10 in there if you fill up the 10 frame.

- [Ms. Tahese] I agree with you Lily, thank you so much.

- [Lily] And then we know how many two is so we can just put in two.

- Yeah.

So in this story, Lily, in our first story we had babies in two cribs sleeping.

With this story, we had babies also in the crib, two cribs.

But now they wanna get up 'cause they're hungry.

So we're gonna figure out how many babies are gonna end up leaving this crib.

So Lily's going to spin to find out, oh, let's write that down, first you write it, Lily.

So let's write 12.

'Cause that's how many babies we have sleeping right now.

Now we're gonna spin and find out how many babies are gonna be waking up and leaving the crib.

- Six.

- Six, okay.

Now when we are doing a take from 10, we wanna look at which crib already has 10 babies in it, right Lily?

So which crib are we gonna take the babies from?

Which crib already has 10 babies in it?

- This one.

- Alright, how many are we gonna take from there?

- Six.

- So let's do that.

- Take away the first five.

Take away one more.

- Great.

So now that we've done that, let's write what we just did in our number sentence over here just to be sure that we don't forget.

So what did we just do?

- 10 minus six.

- 10 minus six.

Which gives us how many, so how many babies are left in our top crib?

- Four.

- Great.

But now we still have some babies in that second crib, they're still sleeping.

So we're gonna figure out how many babies we have in all that are still sleeping.

So we're going to add our top crib to our bottom crib.

All right, so what's our number sentence, Lily?

- Four plus two.

- [Ms. Tahese] Okay.

- [Lily] Equals six.

- So if four plus two equals six, that means 12 minus six must equal... - Six.

- Six.

Great.

Alright, I really like this game, Lily.

Thanks for joining us today.

Bye!

- Bye!