Lesson video

Hello everyone and welcome to maths with Ms. Dobrowolski.

Today, we'll be adding two-digit numbers and ones with regrouping.

Let's have a look at today's lesson agenda.

First, we'll start by reviewing the Make 10 strategy.

Then we'll add two-digit numbers with regrouping.

You'll be off for your independent task.

And finally, you have your final quiz.

So for today's lesson, you will need a pencil and a notebook and possibly some pasta shapes.

If you could get some spaghetti and macaroni or penne, that would be great.

If you don't have the pasta shapes, that's totally fine.

You do not need them to be successful in this lesson.

And I know, what does pasta has to do with maths? Just trust me on this one.

If you don't have these items, you can pause the video now and resume when you're ready.

Great, so let's review.

How can we Make 10? So I have the calculation here, 29 plus 6.

Well, I know that 29 plus 1 is equal to 30.

So I'm going to now partition my 6 or split it into 1 and 5.

And that's because 1 plus 5 is equal to 6 and I need that 1 there because 29 plus 1 is equal to 30.

So on my number line, I can see 29 plus 1 is equal to 30 and now I just need to add the other half of my partition, the 5.

So 30 plus 5 is equal to 35.

That means 29 plus 6 is equal to 35.

Let's try that again.

So let's make a 10.

We have 18 plus 7.

Hm, what 10 can we make using the number 18? Oh, I know, 18 plus 2 is equal to 20.

So I know now that I need to partition my 7 into 2 and 5, because 2 plus 5 is equal to 7.

So now on my number line, I know that 18 plus 2 is equal to 20 and now I'm going to add the other part of my partition, 20 plus 5 which is equal to 25.

That must mean 18 plus 7 is equal to 25.

If you're feeling super confident and you know how to make a 10, pause the video now and do that and then come back so we can compare answers.

If you're not feeling too sure, just stay on with me.

So 18 plus 5, how can we use the Make a 10 strategy? So have a think.

Even using the number line, what 10 we make if we're starting at 18? Hm, oh, 18 plus 1, 2 is equal to 20.

So I know that I have to partition or split my 5 into 2 and 3, because 2 plus 3 is equal to 5.

So again, 18 plus 2 is equal to 20 and now I need to add 3.

So 20 plus 3 is equal to 23.

That must mean 18 plus 5 is equal to 23.

So now we're going to move on to adding two-digit numbers and one with regrouping.

In order to do this, I'm going to use my whole part model.

So let's have a look at this equation.

Something is equal to 46 plus 7.

To help me solve this, I will use my whole part model.

It's really easy to draw this.

You can actually do it at home.

So first I draw one really big box.

That's going to be my whole.

And then I'm going to draw two more boxes that will be my parts.

That's one and that's two.

So my first part is 46.

So I'm going to put 46 in this box using my teens.

I need four tens.

So count with me.

10, 20, 30 and 40.

And now I need six ones.

So you can count with me.

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

Now I need to fill in my other part, which is seven.

So I need seven ones.

Count with me.

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

Great.

When we use a part whole model, we add the ones first to see if we can make any groups of tens.

So 6 ones plus 7 ones.

Let's use our make 10 strategy.

Hmm.

If I have six, how can I make a 10? Oh, I know, 6 plus 4 is equal to 10 plus another 3 is 13.

So let me move 4 ones here, because 6 plus 4 is equal to 10.

Now, since I've made a 10, I can remove the ones and make a group of 10.

What I'm doing here is called regrouping.

I replaced my 10 ones with one 10.

I regrouped.

So now I look at the tens.

I have one, two, three, four tens plus the one I regrouped.

That's five tens and one, two, three ones.

46 plus 7 is equal then to 53, because I have one, two, three, four, five tens and three ones.

Great.

So let's try that with another equation.

This time, I know that something is equal to 57 plus 6.

Now, instead of using tens, I'm going to use a pasta shape.

So I'll use my spaghetti as my 10.

And instead of using my ones, I'll use my macaroni.

So we'll take away those.

And now I have macaroni and spaghetti to act as my tens and my ones.

So if you have these pasta shapes at home, pause the video now and go get them.

Super, so first let's make 57 in our part.

So 57, I need 5 tens.

One, two, three, four and five.

So I have 5 tens.

Okay.

Now how many ones do I need? Oh, I need 7 ones.

One, two, three, count with me, four, five, six, seven.

Okay.

Now we have to make our other part, which is six.

So count with me.

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

Great, so when we use a part whole model, we add the ones first to see if we can make any groups of tens.

So we have 7 ones plus 6 ones.

So again, that's 7 ones plus 6 ones.

Let's use the Make 10 strategy.

Hm, 7 plus something is equal to 10.

What's that something? Oh, that's right.

7 plus 3 is equal to 10.

And then plus 3 is 13.

So we have 7 plus one, two, 3 is equal to 10 and then 10 plus 3 is equal to 13.

So remember when we've made 10 ones, we can trade those in for a 10.

So I'm getting rid of my 10 ones and putting one 10.

So again, that was called regrouping.

Once I had 10 ones, I regrouped and I gave myself one 10.

Great.

So now I look at my tens.

I have one, two, three, four, five tens, plus the one I regrouped so that's six tens.

So we can put those over here.

Six tens and one, two, three ones.

So if I had 6 tens and 3 ones that makes 63.

57 plus 6 is equal to 63.

So let's try that one more time with another equation, something is equal to 38 plus 4.

If you are feeling super confident and you have some pasta shapes to work with, pause the video now and solve the equation using a whole part model that you can draw yourself.

Make sure you identify where you can make a ten first.

If you're not feeling super confident, just stay on with me and we can do this together using our macaroni shapes.

So either way, if you're pausing now or not, just get some macaroni shapes if you have them.

If you don't have any macaroni or spaghetti or pasta shapes, don't worry, you can just follow along with us.

So first we're going to make our first part, which is 38.

So tell me, how many tens do I need? That's right, I need three tens.

So let's get our spaghetti 10, 20, 30.

Remember if you have your spaghetti, you can do what I just did, 10, 20, 30.

How many ones do we have? That's right.

We had eight.

So let's get our smaller pieces of pasta.

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

Super.

Now we need to make our other part, which is four.

So we just have four ones.

One, two, three, four.

Great, remember when we use a whole part model, what do we add first, the tens or the ones? That's right, the ones.

So let's see if we can make any groups of tens.

I had 8 ones plus 4 ones.

Hmm.

Let's use our Make 10 strategy.

I know that 8 plus 2 is equal to 10.

So that's 10 plus 2 is equal to 12.

So now that I have 10 ones here, I'm going to regroup, well done, regroup.

And instead of having 10 ones, we're going to put in one 10.

So make sure you put that spaghetti in there.

Great.

So now let's look.

I have one, two, three, four tens one, two, three, four.

And I have two ones, one, two.

so 4 tens and 2 ones is equal to 42.

So 42 look, 38 plus 4 is equal to 42.

Well done, everyone.

So it's already time for your independent task.

So for this independent task, I'd like for you to figure out how much do the children spend? You have the price of each candy up here, so make sure you look at that.

As usual, we'll do the first one together and then you'll go off on your own.

So it looks like in number one, the child here buys chocolate and a lolly.

Well I can see the chocolate costs 58p and the lolly costs 6p.

so 58 plus 6 is what I'm going to add.

Now I'm going to use my Make 10 strategy to solve this.

I know 58 plus 2 is equal to 60 and then 60 plus 4 is equal to 64.

Yay, I got that right.

Now it's your turn.

Figure out numbers two and three and when you're finished, we'll go over the answers together.

See you when you're done.

Pause the video and resume when you're ready.

Oh, I forgot to tell you, there's a bonus question.

There's a challenge here.

I would like for you to tell me what would you buy and how much would it cost? So again, the challenge is optional.

If you're not feeling too sure, you don't have to do it.

But I think some of you are really keen to have a go.

So pause the video and I'll see you when you're done.

Great job, everyone.

So for number one, we did together.

So we won't go over that again.

In number two, the sweet cost 28p and the other candy here cost 8p.

So that was a total of 36p, 28 plus 8 is equal to 36p and then we had a candy and a lolly, so 36p plus 6p is equal to 42p.

Well done, everyone.

If you'd like to, you can share your work with Oak National by asking a parent or carer to share your work on Instagram, Facebook, or Twitter, tagging @OakNational and #LearnWithOak.

I'd be really keen to see what kind of candy you decided to buy.

As always, don't forget to complete the final quiz before you're finished.

It was really nice to see you and I hope you come back for the next lesson.

Bye now.