Lesson video

Hello, my name is Mr. Goldie, and welcome to today's maths lesson.

I hope you're going to have lots of fun.

And here is our lesson outcome.

Our lesson outcome is, "I can represent addition problems using first, then, then, now, and bar models." And it would be helpful to have some paper, a pencil, and you might want to use tens frames as well today to help you.

And here are our keywords.

So our keywords are addend and sum.

Now an addend is a number added to another number.

So three and five equals eight.

Three and five are the addends in this addition calculation.

The sum is the total when numbers are added together.

So three and five equals eight.

Eight is the sum in this addition calculation.

So our lesson outline, two parts to today's lesson.

The first part is using first, then, then, now to represent addition problems. And the second part is using bar models to represent addition problems. Let's get started.

In this lesson, you will meet Izzy and Alex, and Izzy and Alex are going to help you with your work and ask you some challenging questions too.

Start with our first problem.

So some frogs are sitting on a log.

First, there were three frogs, then two more frogs jump on.

Then one more frog jumps on.

Now there are six frogs on the log.

So that's an example of a first, then, then, now problem.

You can show this problem using a tens frame.

First, there were three frogs.

So instead of frogs, we're going to use counters.

There are our three frogs.

Then two more frogs jump on.

Then one more frog jumps on.

Now there are six frogs on the log.

How could you write the problem as an equation? First, there were three frogs.

There we have three.

So three is one of the addends.

Then two more frogs jump on, plus two.

So two is another addend.

Then one more frog jumps on, plus one.

So one is our last addend, three add two add one.

Now there are six frogs on the log, so equals six, so six is our sum.

So our equation is three add two add one equals six.

Some frogs are sitting on a log.

First, there were two frogs.

Then three more frogs jump on.

Then four more frogs jump on.

Now there are nine frogs on the log.

You can show this problem using a tens frame.

So first there were two frogs.

There are our two frogs.

Then three more frogs jump on.

Then four more frogs jump on.

Now there are nine frogs on the log.

So tens frames are really helpful for helping you solve these problems. How could you write the problem as an equation? So first, there were two frogs.

There's our two.

Then three more frogs jump on.

We're going to add three.

Then four more frogs jump on, we're going to add four.

Now there are nine frogs on the log, equals nine.

So two and three and four are our addends and nine is our sum.

And we'd write the equation as two add three add four equals nine.

Here's Izzy and Izzy's saying, "I spotted that two add three equals five.

And I also know that five add four equals nine." So Izzy's using her near doubles to help her work out the answer as well.

Okay, two and three.

So we can add that together first of all and then add four.

So Alex is icing some cakes.

First, five cakes are iced.

There's our five cakes.

Then five more cakes are iced.

There's another five cakes.

Then three more cakes are iced.

There's our three cakes at the end.

Now there are 13 cakes with icing.

So it is another example of a first, then, then, now problem.

You can show this problem using tens frames.

First, five cakes are iced.

Let's put our five cakes into our first tens frame.

Then five more cakes are iced.

Add another five, because spot of course that makes 10.

Then three more cakes are iced.

There's our three cakes.

Now there are 13 cakes with icing.

How would you write the problem as an equation? So first, five cakes are iced.

So we start with five.

Then five more cakes are iced, so we add five.

Then three more cakes are iced, we add three.

Now there are 13 cakes with icing.

So our sum is 13 and our equation would look like that.

Five add five add three equals 13.

Oh, and Alex is saying, "You can work out the sum of five add five by doubling five." So again, it's using those facts you know already.

And here's one for you to try on your own.

Some frogs are sitting on a log.

First, there were four frogs.

Then two more frogs jump on.

Then four more frogs jump on.

Now there are how many frogs on the log? Represent this problem using a tens frame.

Write the equation.

So pause the video and have a go at that.

Let's see how you got on.

Do you think you got the right answer? Let's find out.

So use a tens frame to represent the problem.

So first, there were four frogs.

So we put four counters in.

Then two more frogs jump on.

That's another two counters.

Then four more frogs jump on.

That's another four counters.

We've completely filled that tens frame.

And our equation would be four add two add four equals 10.

Very well done if you managed to do both of those things.

Our next problem is to work out the equation using the tens frame.

So, our two tens frames there with some counters in.

Can you work out the numbers are? And perhaps we could retell the story using frogs.

There we go.

First, there were how many frogs on the log? Then how many more frogs jump on? Then how many more frogs jump on? And how many frogs are there on the log altogether? So let's start off with our blue counters.

How many blue counters are there? How many frogs are there? There are six, so we're gonna start with six.

How many more jump on, what's our next number we're going to add, we're looking at the red counters next.

Start with eight, so we add on two, and how many more frogs jump on? So our green counters, there are three.

And how many frogs altogether on the log now? We've got 11, so that's our sum.

And our equation would be six add two add three equals 11.

Next, have a go at one of those on your own.

Can you work out what the equation is using the tens frame? And again, you might want to retell the story using frogs as well.

So pause the video.

Can you work out what the number sentence would be? Let's see how you got on.

So first though, how many frogs on the log? Five, so five blue counters.

How many more frogs jump on? So we're looking at the red counters that the frogs that jump on next.

We're adding four.

How many more frogs jump on? So we're looking at the green counters.

Add another four.

And how many frogs on the log altogether? Well, we've got 10 and three more.

So altogether our sum is 13.

So our calculation would be, our equation would be five add four add four equals 13.

Very well done if you managed to solve that problem.

And next, we're onto our tasks.

So you are going to use tens frames to represent these problems and you might want to retell them as frog problems. So how many frogs on the log, how many more frogs jump on, how many more frogs jump on? And then how many frogs are there on the log altogether? So use tens frames to help you work out the answers to those calculations.

So pause the video and have a go at those using tens frames.

Good luck.

Let's look to see whether you were right.

So let's look at our answers.

So there are answers to all the equations.

And now we're going to move on to the second part of the lesson.

So the next second part of the lesson is going to be using bar models to represent addition problems. So you can also use bar models to represent problems. Bar models are incredibly useful in all sorts of different ways, but they're very good for addition problems. Now, a bar model looks like this.

You may have seen a bar model before, but just in case you haven't, here's what one looks like.

There is a bar model.

So the top, we've got our sum.

So that's the three numbers added together.

And at the bottom, we've got our three addends.

So this particular bar model is split into three addends, there are three numbers adding together to make the sum.

The addends add together to make the sum.

Let's use our bar model to help us solve this problem.

So some frogs are sitting on a log.

First, there are four frogs.

There are four frogs, that's one of our addends.

Then three more frogs jump on.

So our next addend is three.

Then two more frogs jump on.

There's two.

Now there are nine frogs on the log.

So we add all those together.

Four add three add two, and that makes our sum.

So four add three add two equals nine.

Some frogs are sitting on a log.

First, there were four frogs, then three more frogs jump on.

Then four more frogs jump on.

How many frogs on the log altogether? You could use doubles to solve this problem.

If we've got four, add four.

Altogether, there are 11 frogs on the log.

Four add three add four equals 11.

Alex is icing some cakes.

So first, three cakes are iced, then three more cakes are iced.

Then four more cakes are iced.

Now there are 10 cakes with icing.

So there's our 10.

Three add three add four equals 10.

So we're adding together our three addends to make the sum.

Bar models can also be used with tens frames.

First, there were five frogs on the log.

There's our tens frame with the five in it and our bar model with five.

Then two more frogs jump on.

There's two more frogs in our tens frame, two more frogs in our bar model.

Then two more frogs jump on.

Another two in our tens frame and another two in our bar model.

And altogether are now nine frogs on the log.

You can see that quite clearly on the tens frame.

On the bar model we put our sum at the top.

So five add two add two equals nine.

Now here's another problem for you to try on your own.

The question is which bar model matches the tens frames? Which bar model matches the tens frames? So have a good look at the tens frames, look at the numbers of counters in the tens frames and see if you can work out which bar model matches those tens frames.

So pause the video, see if you can work out which one it is.

There are six blue counters, three red counters, and two green counters.

So the bar model that has the addends six, three, and two is B.

So well done if you spotted that.

Okay, our next problem is you're going to calculate the sum for each bar model.

And here's Izzy and Izzy is saying, "Can you see any doubles?" So look carefully at the addends.

And can you work out the sum of each of the bar models? So the first one we're doing three add three add one.

So three add three add one would be seven.

Three and three makes six.

One more makes seven.

The next one, we've got four add two add two.

Four add two add two makes eight.

You could add two and two together, first of all, we get four.

And then four and four, of course, is a double too.

That would be eight.

And our last one is four add four add one.

And what would the sum be on that one? So this time, we're doubling four again.

So four add four makes eight, add one more would be nine.

So our sum, our bar model would be nine.

Now here are three bar models for you to try on your own.

Izzy's saying, "Can you see any doubles?" So calculate the sum for each bar model.

Look carefully at the addends and see if you can spot anything to make it easy to add together.

So pause the video and have a go at those three bar models.

Can you find the sum? Okay, welcome back.

Let's see whether you've got those ones right.

So our first one is five add three add one.

There aren't any doubles there, are there? There aren't any near doubles either, but you should have got the answer.

Nine.

Well done if you did.

So five add three add one makes nine.

Next one, we've got six add six add one.

So six add six add one would make 13.

Six add six makes 12, add one more would make 13.

And the last one actually, even though the the answer's going to be the biggest, even though the sum is the biggest, it's possibly the easiest one there, because you should know what five add five is.

Five add five would make 10.

And then all you have to do is to add eight to 10.

So five add five add eight would be 18.

Well done if you got 18, well done if you've got all of those right, or even if you've got some of them right.

Our next problem is we're still using bar models, but this time you're gonna find the missing addends.

So we've got there our bar model, we've got the sum, but what we've got missing is one of the addends.

So it's saying five add two add something else makes 10.

What is that missing addend? I wonder how you'd work that one out.

Let's have a look.

So we could write it as an equation like this.

Five add two add something makes 10.

So you could also represent this problem using tens frames.

So there, we've already got the numbers five and two in the tens frame and all we've got to do is to work out what we have to add to that to get to 10.

Should be quite nice and easy.

Okay, add on three, get to 10.

So our missing number must be three.

Our missing addend is three.

Let's try this one here.

So our sum is still 10, but this time, our addends are four and four.

So four add four add what makes 10? Let's use a tens frame again.

So let's put the four and the four in our tens frame already and we can see straight away what we need to add to that to get to 10.

If we add two more on, we get 10.

So four add four add two makes 10.

And here are a couple of problems for you to try on your own.

So you've got to find the missing addends.

So there are two bar models.

You've got to find which number is missing from the bar models.

So you've got the sum, you've got two of the addends, but what is the third addend? So pause the video, see if you can work out the answers.

Welcome back.

Let's see if you got the right answers.

So our first problem is we've got nine as the sum and our two addends are two and two and we're looking for the third addend.

So two add two add something makes nine.

So can we work out the missing number? Let's use a tens frame to help us work out the answer.

So the tens frame already has two of the addends put in already.

So two and a two.

And we've got to go all the way to nine.

Where would we fill up to on the tens frame? We don't wanna fill it completely.

We're not going all the way to 10 just to nine.

So we would want to leave one space, don't we? One empty square on our tens frame.

So if we put that number in, number five, we go all the way to nine.

Two add two add five equals nine.

So our missing addend, our missing number is five.

Let's look at the other problem.

So our sum is still nine, but the two addends we've got this time are one and two.

So this time our equation is one add two add something equals nine.

What's the missing addend? Again, let's use a bar model to have us work out the answer.

So already it's got one blue counter, two red counters.

All we've got to do is to count up to nine.

So how many counters do you have to add to get to nine? Six.

So one add two add six equals nine.

So our missing addend is six.

Very well done if you got those correct.

And now we're on to task B.

So part one of task B is complete these bar models.

So in some of the bar models, it's the sum that is missing.

In some of the bar models, it is the addend that is missing.

There's a missing addend.

So see if you can work out the answers, and again, use tens frames to help you.

And our second task is Lucas has these number cards.

So he's got the number cards one up to nine.

So you may want to use number cards as well to help you with this.

Find ways to complete the bar model using three different cards each time.

So you can't use the same card twice in any of the bar models.

So, have a go at trying to make the sum 12 using three of the number cards.

If you used it in one bar model, you can use it in a different bar model, but just not in the same bar model.

So pause the video and have a go at those two tasks and best of luck with them.

Let's go on to our answers.

Let's see how you got on.

So there are our answers for part one.

So we've got the sums there and the missing addends.

And here's part two.

These are some of the possible answers, not all of them.

You may have found some different ones and you may have put the numbers in different orders as well.

So you could have used nine add one add two to get to 12.

You could have used eight add three add one, that also makes 12.

Well done if you got some of those or if you've got all of them.

That is absolutely fantastic work.

And here is our summary.

First, then, then, now can be used to describe addition with three addends.

So first, then, and then, there would be our addends.

And the now part would be our sum.

And bar models can represent addition problems too.

So fantastic work today, very well done, and I look forward to seeing you again.