Lesson video

Hello, everyone.

Welcome back to another maths lesson with me, Mrs. Pochciol.

As always, I can't wait to learn lots of new things and hopefully have lots of fun.

So let's get started.

This lesson is called add three addends efficiently by finding two addends that total 10, and it comes from the unit calculating within 20.

By the end of this lesson, you should be able to use your knowledge of number pairs to 10 to add three addends efficiently.

Let's have a look at this lesson's keywords.

Addends, number pair, efficient.

Let's practise them.

My turn, addends, your turn.

My turn, number pair, your turn.

My turn, efficient, your turn.

Well done.

Now that we've practised them, let's use them.

Let's have a look at our lesson outline for today.

The first part of our learning, we're going to find number pairs to 10 to add three addends and in the second part of our learning, we're going to solve problems involving three addends efficiently.

Let's get started with finding number pairs to 10 to add three addends.

Laura and Andeep are here to help us with our learning today.

Are we ready, guys? Let's get started.

Laura and Andeep are discussing a three addend addition.

There were five birds in the tree, four birds in the bird bath, and five birds on the fence.

How many birds were there all together? We can show this problem as an equation.

Five plus four plus five is equal to something.

Andeep has noticed that the sum of these three addends will be more than 10.

I wonder how he knows that.

He can see that two of the addends are five and he knows that double five is 10.

So then when we add four, the other addend, the sum will definitely be more than 10.

A good spot there, Andeep.

I'm very impressed.

So how can we show this then, Andeep? Andeep shows his thinking using a ten frame.

Five birds are in the tree, four birds are in the bath and five birds are on the fence.

Let's put the two groups of five counters on the ten frame first.

We can see that one ten frame is full and there are still more counters.

Then we're going to add the four more counters onto a new ten frame.

Andeep notices that the sum of these three addends is 10 and four more.

10 and four more we know is 14.

So five plus four plus five must be equal to 14.

Well done, Andeep.

A beautiful strategy there.

When we add three addends, we can look for pairs of addends, which sum to ten.

Five add five is equal to 10, then 10 add four is equal to 14.

We can use this as a stem sentence.

Mhm add mhm is equal to 10.

Then 10 add mhm is equal to mhm.

Let's practise that.

My turn.

Mhm add mhm is equal to 10.

Then 10 add mhm is equal to mhm.

Your turn.

Well done.

We're going to be using that stem sentence a lot, so it's a good job that we had a practise of it first.

Before we start using this strategy, let's make sure that we can spot add pairs to 10.

Can you pause this video and match the ten frames to make 10? Once you've matched all of them, come on back to see how you've got on.

This is really gonna help us with our learning today.

So a quick recap is what we need.

Welcome back.

I hope you managed to spot all of those pairs to 10.

Let's have a look.

Four and six pair to make 10, but Andeep remembers that we can also see this as six and four.

Where's our next one then, Andeep? Which one has he joined up now? We can see one and nine pair to make 10, but we can also see this as nine and one.

Next one, we have seven and three to make 10, but we could also see this as three and seven.

Next up, two and eight pair to make 10, but we can also see this as eight and two.

Well done if you managed to spot all of those pairs to 10.

Now, let's use this knowledge.

How could Laura and Andeep solve this equation? Remember, number pairs to 10 can help.

Eight plus two plus six is equal to something.

Use your ten frame to help you if you need to.

Can you find the sum to this three addend addition? Pause this video and come on back once you're ready to see how you've got on.

Welcome back.

Let's see how Laura's got on.

Laura noticed that eight and two make 10, so she put them on her ten frame first.

She then added six.

10 plus six is equal to 16.

So we know that eight plus two plus six is equal to 16.

Well done to Laura and well done to you too if you found that 16 was the sum.

Laura and Andeep now solve an equation without using their ten frame.

They both discuss how they will solve this problem.

Andeep says that he will first double three, which is six because he knows that fact.

Then add six and seven, 6, 7, 8, 9, 10, 11, 12, 13.

Laura, how would you solve this problem? Laura can see seven and three, which is a number pair to ten.

Seven add three is equal to 10, then 10 add three is equal to 13.

They both found that the sum was 13, but which strategy do you think was most efficient? Remember, Andeep, we can look for pairs to 10 when we're adding to make it easier.

Laura's strategy was definitely more efficient than Andeep counting on.

So let's use Laura's strategy to help us with this check.

Can you find any number pairs to 10 in these expressions? Draw a circle around each addend in the pair.

So you've got A, B, and C.

Pause this video, circle those number pairs and come on back once you're ready to do the next part of our check.

Welcome back.

Did you find some number pairs to 10 in those expressions? Let's have a look.

Andeep, have a look at A for us.

In A, we can see nine and one.

This is a pair to 10.

In B, Andeep couldn't find a pair to 10, so there's none to circle.

And in C, we can see four and six.

This is a number pair to 10.

Well done if you managed to find both of those number pairs in A and C.

Now let's do the next step.

Now you've found those pairs to 10, use this to now help you solve each equation.

Remember, you can use our stem sentence to help you.

Mhm add mhm is equal to 10, then 10 add mhm is equal to mhm.

So have a go at A, B, and C.

Pause this video and come on back once you've got a sum for each of those equations to see how you've got on.

Welcome back.

Hopefully with those number pairs to 10 and that stem sentence, you found the sums to these equations rather quickly.

Let's have a look then.

A, we know that nine and one is equal to 10, then 10 add five, that third addend is equal to 15.

Well done if you got 15.

Now B, there wasn't a number pair to 10, so Andeep is going to look for a different strategy.

He can see four and one, which he knows is a pair to five.

Then five add five is equal to 10.

So the sum of this equation is 10.

We didn't have a pair to 10, but all three of these addends are equal to 10 because we have five and a number pair to five.

A good spot there, Andeep.

Did you spot that too? And C, we have our number pair to 10, so four add six is equal to 10, then 10 add nine is equal to 19.

Well done if you got 19 for C and well done to you if you completed all three of those equations.

Now then, over to task A then.

Part one is to sort these expressions to show whether they have a pair to 10 or no pair to 10.

Look at each expression carefully.

If they have a pair to 10, you put them in the pair to 10 column.

If they don't have a pair to 10, you put them in the no pair to 10 column.

And part two, you're going to place a greater than, less than or equal to symbol in each box to show whether the expression is greater than, less than or equal to 10.

Work out the sum of these three addends using the most efficient method.

Then use our stem sentence to help you to choose the correct symbol.

Mhm is greater than mhm, mhm is less than mhm, or mhm is equal to mhm.

Thanks for the reminder there, Andeep.

Pause this video, have a go at part one and part two and come on back when you're ready to see how you've got on.

Enjoy.

Welcome back.

Let's see how you got on.

So part one, we had to sort the expressions to show whether they had a pair to 10 or no pair to 10.

Are we ready? Five plus two plus five.

I can see five and five, which is a pair to 10.

So that goes into this column.

Six plus three plus seven.

Can we see a pair to 10 there? Yes.

Three and seven are a pair to 10.

Four plus four plus one.

I can't see a pair to 10 there, so that needs to go in no pair to 10.

Six plus eight plus two, yep, eight and two, I can see it.

Two plus three plus one.

No pair to 10 there.

Seven plus six plus five.

No, I can't see a pair to 10 there.

Nine plus zero plus one.

Yep, nine and one are a pair to 10.

And five plus three plus five.

There's that double five again, we know double five is 10.

Well done if you managed to sort those into the correct columns.

Now let's look at part two.

So we were placing greater than, less than or equal to symbols to show whether these expressions were greater than, equal to or less than 10.

Let's have a look then, Andeep.

Double four is eight, add one is nine and we know that nine is less than 10.

So four plus four plus one must be less than 10.

Eight and two is that number pair to 10 and we add four more, which is 14.

We know that 14 is greater than 10, so two plus four plus eight is greater than 10.

Double five, we know that that double five is a number pair to 10, add one more, which is 11.

11 is greater than 10.

So we can say that five plus one plus five is greater than 10.

We can't see a number pair to 10 here, wait a second.

Andeep has spotted two add one, which is three and we know that three and seven is a number pair to 10.

So 10 is equal to 10.

Seven plus two plus one is equal to 10, which is equal to 10 and we can see that eight and nine will sum to be more than 10.

So this has to be greater than 10.

Eight plus four plus nine is greater than 10.

Well done for completing task A.

Let's have a look at the second part of our learning: solving problems involving three addends efficiently.

Let's get started.

Laura and Andeep are looking at their table's sticker reward chart.

How many stickers do Sam, Alex and I have all together? Oh, good question, Laura.

How are you gonna work that out? Sam has four stickers.

Laura has six stickers and Alex has nine stickers.

To find out how many all together, we have to add these three numbers.

We can see that four and six is a number pair to 10.

Look, if we pop them on top of each other, we can see on our grid that we can make 10.

Now we can use our stem sentence.

Four add six is equal to 10.

10 plus nine is equal to 19.

So Sam, Laura, and Alex have 19 stickers all together.

Some good use of our stem sentence there, Laura.

Well done.

Andeep now wants to see how many stickers he, Izzy and Alex have all together.

Andeep has one sticker.

Izzy has three stickers and Alex has nine stickers.

To find out how many all together, we have to add the three numbers together.

We can see one and nine, which is a number pair to 10.

Look, if we add nine and one that will equal to 10.

Now we can use our stem sentence.

One add nine is equal to 10.

Then 10 add three more is equal to 13.

So we know that Izzy, Alex and Andeep have 13 stickers all together.

Laura says that if she adds her stickers with Sam and Izzy's stickers, they would also have a sum of 13 stickers.

Is Laura correct? How do we know? Pause this video, have a think and an explore and come on back once you're ready to say if Laura is correct or not.

Welcome back.

I hope you did some good thinking there.

Let's have a look.

Is Laura correct? Laura already knows that her stickers and Sam's stickers are equal to 10 because they are a number pair to 10.

Then 10 add three, which is Izzy's stickers, are equal to 13.

Laura was correct.

Four plus six plus three would be equal to 13.

She just swapped the number pair to 10 from nine and one, which were Andeep and Alex's stickers, to her and Sam's stickers, which were four and six.

Well done there, Laura.

A really good spot there.

The next day, Laura and Andeep and Alex earned more stickers for helping Mr. Acorn tidy up the classroom.

Laura earned five stickers.

Andeep earned eight stickers and Alex earned two stickers.

How many stickers did the children earn all together? The children use a part-part-whole model to represent their calculation.

Laura has five stickers, so five is a part.

Andeep has eight stickers, so eight is a part and Alex has two stickers, so two is a part.

The children must now find the sum to see how many stickers they have all together.

Alex has suggested that to find the whole we must add five, eight, and two.

Let's first write this as an equation.

We can write this as five plus eight plus two is equal to something.

Andeep has spotted that there is an eight and a two, which are a number pair to 10.

We then add the five because that's our third addend.

So 10 plus five is equal to 15, so five plus eight plus two must be equal to 15.

The children must have 15 stickers all together.

Wow, Mr. Acorn was feeling very generous for them helping to tidy.

Over to you then.

Can you create a part-part-whole model to represent this problem and find out how many stickers the children have all together? Laura earned seven stickers, Andeep earned five stickers and Alex earned five stickers.

How many stickers did the children earn all together? Pause this video, create your part-part-whole model and find the whole.

Come on back once you're ready to see how you've got on.

Welcome back.

Let's see what the part-part-whole model should have looked like.

Laura had seven stickers, so seven is a part.

Andeep had five stickers, so five is a part.

And Alex had five stickers, so five is another part.

Now let's see how Laura found the whole for her part-part-whole model.

We can write our equation as seven plus five plus five is equal to something.

Five and five is equal to 10.

Then 10 add seven is equal to 17, so seven plus five plus five must be equal to 17.

The children had 17 stickers all together.

Well done to you if you worked out that they would have 17 stickers all together and well done if your part-part-whole and equation looked like Laura's.

Over to you then for task B.

Part one is to fill in the missing numbers and explain your steps using our stem sentence.

So find the sum to these three addend additions and use the stem sentence to explain how you worked it out.

Once you've solved these, what knowledge can you use to apply to solve these equations? Ooh, I can see some four addend additions.

Don't worry, you can use this knowledge to help you to solve them.

And part two, using the table sticker chart, can you solve these problems? A, how many stickers do Aisha, Jacob and Laura have all together? How many stickers do Laura, Andeep and Izzy have all together? And C, which three children have a total of 12 stickers? Find more than one answer.

Write an equation for each of these problems to show how you worked it out.

Have a go at task B, part one and part two and come on back when you're ready to see how you've got on.

Welcome back.

I hope you found those tasks really fun now that you have all the knowledge that you need to solve them.

Let's have a look at part one.

Come on then, Andeep, how did you solve the first one? Six and four is equal to 10, then 10 add one is equal to 11.

Well done if you got that one.

Eight and two is equal to 10, then 10 add seven is equal to 17.

So that one is equal to 17.

Five and five is equal to 10.

Then 10 add four is equal to 14.

Now, how did you apply your learning here, Andeep? Here we can see that there are four addends, but we're still going to look for a pair to 10.

One and nine is equal to 10.

Wait, so is four and six.

That's equal to 10 too.

Then 10 add 10 is equal to 20, so well done to you if you spotted that that was equal to 20.

Now, here we can't see a number pair to 10, but we do know that two add one is equal to three and three add seven is equal to 10.

We added the three addends to sum to 10 and then we added the four, which is 14.

Well done if you completed all of those problems. Let's have a look at part two.

Part two, part A was how many stickers do Aisha, Jacob and Laura have all together? We can see that Aisha had eight stickers.

Jacob had two stickers and Laura had six stickers.

Eight and two is equal to 10.

Then we add that third addend, so 10 plus six is equal to 16.

We can see that eight plus two plus six is equal to 16.

So Aisha, Jacob and Laura have 16 stickers all together.

Well done if you solved that one.

Let's have a look at B.

How many stickers do Laura, Andeep and Izzy have all together? Laura has six stickers, Andeep has one sticker and Izzy has three stickers, but Laura can't see a number pair to 10.

Wait a minute, what's she spotted? Three and one is equal to four and six and four are a number pair to 10, so the sum must have been 10.

Six plus one plus three is equal to 10.

So Laura, Andeep and Izzy have 10 stickers all together.

Well done if you spotted that.

And C, which three children have a total of 12 stickers? Find more than one answer.

Hmm.

If I use my pairs to 10 knowledge, 12 can be seen as a pair to 10 add two.

Sam and Laura's stickers make a pair to 10 because four and six is equal to 10.

Then 10 add two is equal to 12, so Sam and Laura's pair to 10, plus Jacob's two would be equal to 12.

So we can say that Sam, Laura, and Jacob have 12 stickers all together.

Alex and Andeep's stickers also make a pair to 10, so nine and one is equal to 10.

Then 10 add Jacob's two stickers is equal to 12, so you might have found that Andeep, Alex and Jacob also had a sum of 12 stickers.

Well done if you found both of those answers and well done for completing task B.

Let's have a look at what we've covered today.

The order of addends can change and the sum stays the same.

When adding three addends, it is efficient to first find two addends that sum to 10.

Mhm add mhm is equal to 10.

Then 10 add mhm is equal to mhm.

An example of this is six and four is equal to 10.

Then 10 add one is equal to 11.

Thank you so much for all of your hard work today.

I'm hoping that number pairs to 10 have made your adding of three addends even easier for you.

I can't wait to see you all again soon.

Goodbye.