# Lesson video

In progress...

Hello, and welcome to today's lesson.

We're going to be continue with our unit, exploring calculation strategies.

And today our session is going to be based on adding two 2-digit numbers using the column method.

For this lesson, you'll need a pencil and some paper.

Please pause the video now to get these things if you haven't got them already.

Right then, I thought we'd start today's lesson with a little riddle.

People buy me to eat me, but never eat me.

What am I? Have a little think, what do you think that could be? People buy me to eat me, but never eat me.

What am I? I am cutlery.

So, let us get started with today's lesson.

So, our agenda for this session.

We're going to be learning how to use column methods for adding two 2-digit numbers together.

We're going to start with a quiz to test your knowledge, then we're going to look at today's star words, we're going to look at how we partition and pictorial models that we can use to help us, then you're going to talk about your talk tasks.

We're going to look at how we can use column method both with dienes and with written numbers.

You'll then have a chance to have a go at your independent task, and we'll review the answers together and finally, there'll be a quiz to see what you've remembered from today's session.

Okay then, let's get started with doing today's star words.

We're going to use my turn, your turn.

So, listen carefully.

Place value.

Tens.

Ones.

Column.

Is equal to.

Okay, let's have a look at today's new learning.

Right then, our new learning today.

We've got an equation that says 32 plus 41 is equal to, and we don't know the answer.

So, I want you to look at it happily at my part part-whole model.

I know the two parts here and here, but I don't know my whole at the moment.

I want you to think about my question.

How can I partition the numbers? Give yourself five seconds thinking time and then we'll go through how I partitioned them together.

Okay, let's see them.

Well done today.

If you noticed, I positioned them into tens and ones.

So let's start.

I've got 30, one, two, three, three tens, two one, two ones 32.

And here I've written an in an expanded way.

So I've got 30 plus two.

So I petitioned it again into my tens, and my ones.

Got the pictures and the diens to help me.

And I've got the written numbers.

My next number was 41.

I've got one, two, three, four times, and one, one, therefore, 41.

Again, I've written it in a column method.

I've got 40 plus one.

Now, I've got these and I've partitioned them.

I still don't have my answer.

So let's take a look at a method that I could use to get to my answer today.

So, let's have a look here.

We've got our diens and we've got it written in an expanded method.

We've got 32 here, a 41 here.

We're going to start as we did before with our ones.

So let's do this.

Okay.

We've got, One, two-ones and one three.

So that would give me, three ones.

We've got one, two, three down here.

And I've written three here as well.

Let's have a look at that tens.

Then we've got, one, two, three, four, five, six, seven tens.

I should have seven, tens, one, two, three, four, five, six, seven tens.

So I've got 70 here, 7 tens and three ones, is 73.

We could write that as 70 plus 3.

Having done that, then, Our second example today.

This time I've got 67 plus 22 is equal to.

Again, I've used my part part-whole.

I don't know my whole, what's really happening at my two parts.

And how do you think again about how I've partitioned the numbers? Give yourselves five seconds thinking time, then we'll go through the answers.

while I was in today's, If you noticed again, we've used petitioning into tens and ones to get our answers.

So, here, it was 67, got one, two, three, four, five, six, tens, that's 60 and one, two, three, five, six, seven ones.

There's seven ones.

And here we've got one two, So two tens or 20 and one, two ones or two, 22 Let's see how we can add them together.

So again, I've used my dienes here and I've used my expanded methods here.

So we're going to add them up.

You've got one, two, three, four, five, six, seven, eight, nine.

So I've written my here.

Let's just double check.

I've got nine here.

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

When now we're looking at our tens, let's see what happen, one, two, three, four, five, six, tens, for sixty, seven, eight hands and title one, two, three, five, six, seven, eight, tens.

Well, eight tens.

I can recombine that number to give me 89.

Then my answer would be 89.

Now, it's time to go to tasks.

You have got six different equations on your screen.

What I'd like you to do is choose an equation, partition, both of the numbers and use the expanded method to add them together.

So for example, I could choose 32 plus 41, the first one here.

I could expand that into 32 into 30 plus two, and 41 into 40 plus one.

I can do 30 plus 40 is 70, and two plus one is three, written by name, 70 plus three is equal to 73.

Don't forget to use your say out loud.

This number has tens and ones.

Close the video and hope to have today's talk task.

Welcome back.

Next act, develop learning today.

So develop learning to job.

We're going to be looking at the same equations that we've just looked at.

We're going to be looking at how we can answer them using a slightly different method called the column method.

So let's have a look.

Firstly, what our numbers looked like when we put them into a tens and ones grid, just about see it behind.

So we have our dienes just like we had before.

We have our first number here, We have a three tens, but that's tens and I have two ones digit.

So that number should be 32, we then have 41 represented here with our dienes.

We have four tens and one, one.

Then them just like we did before, add using our ones spot and then our tens next.

And that we have three ones on seven tens.

It's going to look a little bit different now, but really look for one red on the right.

But then what's the same and what's different between these two grids? Well done to those of you who spoke it.

This grid here uses just our dienes, this one here uses just our numbers.

We can see here, two ones, still two ones, three tens, is still three tens.

I don't need to put a zero here, because my columns labelled tens.

So it's just the three, because that three represents three tens.

Next, I have 41.

I have one in my ones, and I have four tens, Again, I don't need to put a zero, because my four represents four tens.

And I know that if I look at the top of my column, then I start from my ones.

Now, I know it's not really three Apple.

It's really three tabs are full.

Tens is seven tens.

But I can say tabs full is seven, because I know that that's underneath my tens column.

So I know that seven represent seven tens.

That's some of that, that my second example, 67 plus 22 is equal to.

Let's state represented in my columns using my diens again.

We've got our 67 and our 22 here.

When we look over here, we have our seven ones and our six tens.

We then have our two ones and our two tens.

Again, we add our ones first to give us nine.

Then we add our tens to give us eight, eight tens, or 80.

Let's have a look at what this looks like with our numbers, just our numbers.

We add our ones, seven and two equals nine, which is equal to nine and six add two is equal to eight.

Again, I know that six and that two represent tens, six tens and two tens.

So my answer is not just eight.

I know it's eight tens.

But I don't have to write that, because my columns already labelled that.

I think it's time for independent task.

Let's have a look at what it is.

So, you have got six equations here.

What I'd like you to do is have a go at answering these equations.

Remember you can use one of these three methods.

You could draw out using Diens.

You could use the expanded method that we used in our full task, Or you can have a go at trying to use the column method to solve the equations.

Why don't you talk with it and see if you can notice any patterns in the numbers.

If you can, can you explain them? Don't forget to use this column grid, if it's helpful for you.

I play them well done you too.

what we're going to do now is, we're going to go through those answers together.

So, I've got 54 plus 34 is equal to 88.

I've got 44 plus 34 is equal to 78.

And I've got 34 plus 34 is equal to 68 Next column, I've got 71 plus 36 is equal to 107.

I've got 71 plus 35 is equal to 106, and I've got 71 plus 34 is equal to 105.

Did any of you spot the pattern? Well, I've noticed that a mass is here.

My tens 88, 78, 68 are all decreasing.

They're going down in one 10 at a time.

And I find that pretty pathway at the numbers in my equation.

I can see that that 54, 44, 34, are also decreasing in a step.

So that's my pattern next slide.

Okay.

Because my practise is different on this side here, but seven 107 sorry, 106, 105.

This time, my answer is decreasing one each time in my ones column, it's really halfway, 71 each time, Oh, I'm left with six 36, 35, 34.

Each time they're decreasing by one, my answer decreases by one.

Well done, for really, really working hard today.

Please pause the video to have about the final place to, the last few questions for today's session.

See you again soon.

Thank you.

And bye bye.