Lesson video

Hi, everyone, welcome back to our unit on place value.

Today, our lesson is going to be all about adding 10 and adding 100 and subtracting 10 and 100 from numbers.

But before we begin, put on your hats, tighten neck ties and tell the computer now I'm a mathematician, great job.

Let's get started.

Here is our lesson agenda today.

First off, we're going to be doing our star words, we're going to be adding and subtracting 10, adding and subtracting 100 then adding and subtracting with regrouping, and then at the time, your independent task and your quiz.

So before we begin, please make sure you have your pencil, a piece of paper and a ruler.

If you need to get any of these resources please pause the video now, and et's get started.

Star Words; add, subtract, more, greater, less, smaller, increase, decrease.

Now let's remember to use these Star Words together.

Please if you see I'm not spotting if you spot me not using them make sure you whisper madam we have to use Star Words and I'm sure I will hear it.

Here we have to number 112.

And we can represent 112 with one hundreds, one 10 and two ones.

But what happens when we add a 10? Well, so we're adding a 10 sets second 10 dean stick appears here, and then this number changes and it becomes 122.

How about we add another 10? Well, you can see the deans tens have increased, and so has this number by hundreds, and our ones have stayed exactly the same.

Here we have 142.

Here you can see we have our four tens, our hundreds and ones haven't changed.

So each time we increase the amount in our tens column, we can see this number has increased also.

So now we're going to subtract 10.

Now we're not touching our hundreds, we're not touching our ones.

We're just touching our tens.

Here we have four tens in 142.

So if we take away a 10 it will become 132.

And again 122 and again 112.

You can see we just have one tens dean left and one what one 10 in our tens column.

So now we're going to add some hundreds.

Here I thought 112 and this time, we're going to increase our hundreds so our hundreds columns going to increase, and our hundreds here is going to get greater who can see much each ups up? So we have a second hundreds dean.

Our tens to stay the same, our ones to stay the same and this number has increased.

Here we have 312.

So our hundreds have increased in our place value hundreds has increased up to 412.

And again, it has jumped up every time we add 100.

What about subtracting? What do you think is going to happen when we subtract 100? Is the number going to increase or decrease? Whisper to the screen now? You're absolutely correct, it's going to decrease.

So this number will decrease and here will decrease but our tens and ones will stay the same.

So our 412 magic becomes 312, there is three and three, subtract again becomes 212.

And our two is here and our two is here.

And you might have seen it in subtracting and it becomes 112.

We have one hundreds, one tens and two ones.

If I want to subtract 100, if I would see in a question 112 drop 10, I need to cancel out that 10 and I will be left with 102.

You see there's a zero in my tens column.

So it's going to be your turn, you're going to be doing some adding tens, adding hundreds, subtracting tens and subtracting hundreds from original numbers.

As you can see, if this person here I've done fully, the original number is 134.

I've added 10, so 134, add 140, excuse me.

134 add 10 is equals to 144.

Then our next column says add 100.

Okay, back to 134, add 100 is equals to 234.

Pause this video and write all the answers.

Super job everybody, let's go through them together.

67 add 10 is equal to 77 and 67 add 100 is equal to 167.

761 add 10 is equal to 771.

761 add 100 is equal to seven should be 861.

531 add 10 is equal to 541 and 531 add 100 is equal to 631' Great job for you adding, now let's do the subtraction.

165 subtract 10 is equal to 155 and 165 subtract 100 is equal to 65.

251 subtract 10 is equal to 241, and 251 subtract 100 is equals to 151.

741 subtract 10 is equal to 731 and 741 Subtract 100 is equals to 641.

928 subtract 10 is equal to 918, and last but not least 928 subtract 100 is equal to 828.

Goodness me, give yourselves a great big pat on the back.

That was a lot of adding and subtracting we've just done together.

So we're going to see some adding and subtracting with some regrouping now.

So here we have the 193.

You can see I have one hundreds dean, nine tens deans and three ones.

But what happens when I want to add one more 10? I've got 10 one to my tens, mh mh mh, I cannot do that.

I need to change that into another hundreds dean.

So the answer is 203.

'cause if we have 10 ones that makes 110 tens that makes 100 and we need to move that 100 from our tens into our hundreds column.

So here we have our 203.

However, what happens if I want to subtract? Okay, what am I going to do? Well, we are going to exchange that hundred into 10 tens.

So we are going to exchange it, and there it is.

So there we have one hundreds, 10 tens and three ones.

And now we can easily just subtract one of the tens deans to make it back to 193.

So today we're going to be using or adding tens, subtracting tens, adding hundreds and subtracting hundreds knowledge, and we're going to be doing some questions.

So we're going to read the cash question carefully and underline the key information write your equation, solve the equation and write our answers, so here we go.

234 people were at the top of Blackpool Tower.

The lift brought 10 more people to the top.

How many people were there altogether? So my key information is 234 people add 10 more that is 234 add 10.

So I've written my equation and I need to make sure I include my is equals to.

So I know that I need to increase my tens by one more, so the answer becomes 244 people.

So that is what you are going to be doing now.

Then here we have six questions.

So please pause this video, read through the question carefully, and write your answers.

Great job everybody.

Let's go through these together.

John had scored 232 points in the darts game.

With his last dart he scored 100.

What was his total score? So the key information here is 232 and 100, and we need to add them together.

So your answer will be 332.

Question two, 761 people were in the theme park at 5:30 p.

m.

At 6 p.

m 100 people left on coaches.

How many people were left? So what we do is 761 subtract 100, which is 661.

Questions three.

On Monday, 899 people had ridden the rollercoaster before it's last ride.

The last ride had 10 people in it.

How many people went on the rollercoaster altogether? So our key information is 899 people and the last ride had 10 people so we do 899 add 10, which is equal to 909.

Question four, Ben scored 105 in the darts game.

Sophie scored 10 less.

What was Sophie's score? Our key information is 105 subtract 10 which is equal to 95.

Question five; The Pepsi Max roller coaster stands an impressive 68 metres high, and is the tallest roller coaster in the UK.

If it were made 10 metres taller, how tall would it be? So we need to do 68 add ten which is equals to 78.

And finally question states, Petco spent 10P less at the hot dog stand than Josh.

So you need 10 P less.

He spent 255 P, how much did Pippa spent? So we need to do two pounds of 55 P subtract 10, which is equal to two pounds and 45 pence.

Great job today everyone you have all been super dupers and give us a big old pat on the back.

If you'd like to please ask your parent or carer to share your work with Instagram, Facebook or Twitter, tagging @OakNational and #LearnwithOak.

But before you go anywhere, remember to complete the quiz at the end of the lesson.

Hope to see you again soon, bye.