Lesson video

Hello, my name's Mrs. Cornwell and I'm going to be helping you with your learning today.

I'm so pleased we're working together.

I know you'll work really hard and I think we're going to do brilliantly.

So let's get started.

So today's lesson is called Crossing the Tens Boundary Counting Forwards and Backwards, and it comes from the unit Patterns in Counting from 20 to 100.

So we're going to be pattern spotters today in today's lesson.

We're going to be looking for those patterns that can help us when crossing the tens boundary.

And by the end of today's lesson, you should feel much more confident counting forwards and backwards within 100.

So our words that are going to be important for us today are forwards my turn, forwards your turn, and backwards my turn, backwards your turn, and cross the tens boundary.

Cross the, my turn, cross the tens boundary, your turn.

So in the first part of today's lesson, we are going to count forwards and backwards within 50.

And then in the second part of the lesson, we'll count forwards and backwards within 100.

So in this lesson, you will meet Aisha and you will meet Lucas.

They'll help us with our learning today.

So we've got a 100 square here and we're going to start at one and count forwards to 50, pointing to each number as you count.

Think about where you will continue your count when you reach the end of each row, where will you go.

Okay, you ready to count with me? One, two, three, four, five, six, seven, eight, nine, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50.

Well done.

Excellent counting.

So now we're going to count backwards from 50 to one, pointing to each number as we count.

Now this time, you're going to think about where you'll continue your count when you reach the start of each row.

Watch carefully for that.

Are you ready? So we'll start at 50.

50, 49, 48, 47, 46, 45, 44, 43, 42, 41, 40, 39, 38, 37, 36, 35, 34, 33, 32, 31, 30, 29, 28, 27, 26, 25, 24, 23, 22, 21, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, nine, eight, seven, six, five, four, three, two, one.

Excellent.

Well done.

That was really good counting.

So now look at the number track and count forwards from 20 to 40 and back again.

Okay, so it looks a little bit different, but the order of counting is just the same.

Are you ready? 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40.

So now we're going to practise counting back again.

Are you ready? 40, 39, 38, 37, 36, 35, 34, 33, 32, 31, 30, 29, 28, 27, 26, 25, 24, 23, 22, 21, 20.

Excellent.

Which numbers are easy to remember and why? That's right.

So they all follow the same pattern, don't they? You've got the 20s there and the 30s.

And they all follow that pattern that ends one, two, three, four, five, six, seven, eight, nine.

They all have that at the end of their numbers.

Which numbers are harder to remember and why? That's right.

So the decade numbers 30 and 40 are there, but they change when you cross the tens boundary.

So 40 turns to 39 and 30 changes to 29.

So the pattern of counting changes, doesn't it? Lucas is counting forwards from 34.

He says, "35, 36, 37, 38, 39, 30." What mistake has been made? That's right, after the 30s, you count the 40s.

So after 39, he should have said 40.

Now it's time to check your understanding.

So the number after 49 is, so you can either choose 30 or 50 or 40.

Pause your video now while you have a try.

Okay, so what did we say? The number after 49 is 50.

That's right.

Excellent.

Aisha is counting backwards from 43.

She says, "42, 41, 40, 29, 28, 27." What mistake has been made? That's right, when counting backwards, the 30s are before the 40s.

So before 40, she should have said 39.

Oh, now it's time to check your understanding again.

So true or false, when counting backwards, the number before 50 is 39.

So you've got to say whether it's true or false, then you've got to justify your answer.

So you've got to either say it's true, because the number before a decade number always ends in nine or it's false, because the number before 50 has to be in the 40s.

So pause a video now while you have a try at that.

That's right.

It's false, isn't it? Okay, and why is it false? So it is false because the number before 50 has to be in the 40s, doesn't it? So it does end in a nine, but it has to be 49.

Well done.

You can use the patterns in numbers to help you count forwards across the tens boundary.

So count forwards from 37.

So we're going to think about those patterns.

Remember, when the number ends in nine, it's followed by the next decade number.

Are you ready? 37, 38, 39, 40, 41, 42.

Well done.

You can count in a different way across the tens boundary.

So count four was from three tens seven.

But remember when the number ends in a nine, it always is followed by a decade number, isn't it? Are you ready? Count four was from three tens seven, So we've got three tens seven, three tens eight, three tens nine, four tens.

Four tens one, four tens two, excellent.

You can also use the patterns in numbers to help you count backwards across the tens boundary.

So we can count backwards from 43, can't we? And remember, the number before a decade number always ends in a nine.

So that can help us, can't it Are you ready? 43, 42, 41, 40, 39, that's right, 38, well done.

Okay, and you can count backwards across the tens boundary in a different way.

You can start with four tens three.

So remember when you get to the decade number, four tens, the number will, before it will end in a nine, won't it? Are you ready? Count backwards from four tens three.

Four tens three, four tens two, four tens one, four tens, and then it's three tens nine, three tens eight, well done.

Count forwards on your 100 square in two ways.

So I start my count at 28 and I count.

So 28, 29, 30, 31, 32, well done.

Now we can count in a different way.

I start my count at two tens eight, and I count two tens eight, two tens nine, three tens, three tens one, three tens two.

Well done.

Did you spot the pattern when we crossed the tens boundary? Excellent.

So now it's time to check your understanding again.

Count forwards on your 100 square in two ways.

So first of all, you're going to start at 38.

I start my count at 38 and I count.

Okay, so pause the video now while you try that.

Now let's do that together.

So I start my count at 38 and I count, 38, 39, 40, 41, 42.

Excellent.

Now you're going to count in a different way.

I start my count at three tens eight, and I count.

So pause the video while you try that.

Okay, so let's do that together now.

So I start my count at three tens eight, and I count three tens eight, three tens nine, four tens, four tens one, four tens two.

Excellent, well done.

So your task for the first part of today's lesson is here.

You've got Lucas and Aisha, okay? And you're going to count forwards to 50 and backwards from 50 in pairs.

Taking it in turns to say 10 numbers.

When you reach the decade number, flash your 10 fingers, so your partner knows when to take over the count.

Try changing your voice each time you take over the count.

So for example, Lucas might go in a whisper, "One, two, three, four, five, six, seven, eight, nine, 10." Then Aisha would take over the count.

Lucas would flash his fingers at 10, and then she would take over in a different voice and she's chosen a loud voice, "11, 12, 13, 14, 15, 16, 17, 18, 19, 20." Okay, so pause the video while you try that now.

So let's see how we got on.

So there's Lucas and he's counting up to 10 in a whisper.

So he goes, "One, two, three, four, five, six, seven, eight, nine, 10," and flashes his 10 fingers.

Then Aisha takes over and she chooses a loud voice and says, "11, 12, 13, 14, 15, 16, 17, 18, 19, 20," flashes her fingers.

Then Lucas chooses a squeaky voice, "21, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30," and flashes his fingers again.

And then Aisha chooses an angry voice.

"31, 32, 33, 34, 35, 36, 37, 38, 39, 40." So hopefully you're feeling much more confident about counting forwards and backwards now, and we're ready for the next part of our lesson.

So we're going to practise now counting forwards and backwards within 100.

And remember, we're going to be looking for those patterns, aren't we? So here we've got a 100 square and we're going to start at one and count forwards to 100, pointing to each number as we count.

Think about where you will continue your count when you reach the end of each row, okay? Are you ready to count with me? One, two, three, four, five, six, seven, eight, nine, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100.

Excellent.

That was really good counting, wasn't it? Okay, so now we're going to start at 100 and count backwards to one, pointing to each number as you count.

Remember to think about where you'll go when you get to the start of the row this time.

Okay, are you ready? 199, 98, 97, 96, 95, 94, 93, 92, 91, 90, 89, 88, 87, 86, 85, 84, 83, 82, 81, 80, 79, 78, 77, 76, 75, 74, 73, 72, 71, 70, 69, 68, 67, 66, 65, 64, 63, 62, 61, 60, 59, 58, 57, 56, 55, 54, 53, 52, 51, 50, 49, 48, 47, 46, 45, 44, 43, 42, 41, 40, 39, 38, 37, 36, 35, 34, 33, 32, 31, 30, 29, 28, 27, 26, 25, 24, 23, 22, 21, 20 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, nine, eight, seven, six, five, four, three, two, one.

Yeah, well done.

That was really good counting again there.

So you can use the patterns in counting in numbers to help you count forwards across the tens boundary, can't you? We've done that with numbers to 50.

So count was from 68 this time.

So we've got 68 there, haven't we? And remember what happens when we get to a number ending in nine, we get the next decade number.

So 68, 69, 70, 71, 72, 73, 74.

Excellent.

Which was the hardest part? That's right.

It's getting to that 69 and crossing into the next decade, isn't it? Crossing that tens boundary.

Well done.

And we're going to check your understanding again.

So you're going to count forwards across the tens boundary counting from the numbers shown.

So we can see we've got 78 there.

So pause the video while you try.

Okay, now let's try together.

78, 79, 80, 81, 82, 83, 84.

Well done.

Did you manage to cross that tens boundary from 79 to 80? Well done.

You can use the patterns in numbers to help you count backwards across the tens boundary, can't you? So we're going to count backwards from 63.

Are you ready? 63, 62, 61, 60, 59, 58, 57.

Which was the hardest part there? That's right.

Crossing that tens boundary from 60 to 59 was the bit that's hardest to remember, isn't it? Well done.

Okay, so we're going to check your understanding again.

So you're going to count backwards across the tens boundary from the number shown.

And you can see the number there is 83.

Okay, so pause the video while you try that.

Okay, and now let's do it together.

So, 83, 82, 81, 80, 79, 78, 77.

Well done.

So we've got a 100 square now.

Count forwards on your 100 square in two ways.

I start my count at 68 and I count.

68, 69, 70, 71, 72.

Well done.

You can count in a different way as well, can't you? You can say I start my count at six tens eight, and I count.

Six tens eight, six tens nine, seven tens, seven tens one, seven tens two.

Now, can we count backwards on your 100 square in two ways? Let's try.

I start my count at 72 and I count.

72, 71, 70, 69, 68.

That's right, and now let's count in a different way.

I start my count at seven tens two, and I count.

Seven tens two, seven tens one, seven tens.

Six tens nine, six tens eight.

So your task for the second part of today's lesson is to choose a strip to read to your partner and count from the number at the start of the arrow.

The arrow will show you whether to count forwards or backwards.

Use a stem sentence to describe your count to your partner.

So you'll say, I start my count at, mm, and I count forwards to, mm.

Will I say the number, mm? Remember if your arrow points backwards, you have to say backwards in your stem sentence, don't you? If you have to count back.

Okay, so here, it would be, I start my count at 35 and I count forwards to 54.

Will I say the number 45? And then you've got to say whether you'll say that number and explain how you know that you're right, and then you can prove it by counting.

So pause the video now while you try that.

Let's see then, how did we get on? So here's, you may have tried a couple of these examples.

I start my count at 35 and I count forwards to 54.

Will I say the number 45? So Lucas is here and he's saying, "I know I will say 45, because it is in the 40s, which is after the 30s, but before the 50s.

And I will prove it by counting." So he explained how he knew there, didn't he, and then he is going to prove it.

So he'll say, "35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45," so he did say 45.

He hasn't got to 54 yet, so he hasn't stopped counting.

Okay, and let's look at a different example now.

So we've got, I start my count at 35 and I count forwards to 54, but this time, will I say the number 26? So let's see, we've got Aisha here, and she's saying how she knows.

She says, "I know I won't say 26, because it's in the 20s, and I count the 20s before the 30s, so I will prove it by counting.

And so she'll count up from 35 to 54 and she'll know, she'll prove she won't say 26, will she? Okay, so well done.

You've worked really hard in today's lesson, haven't you? And hopefully you're feeling much more confident about counting forwards and backwards across that tens boundary.

So let's think about what we've learned in our lesson today then.

So we found out that the numbers from zero to 100 have patterns that can help us to count forwards and backwards across the tens boundary.

They are arranged differently on a number track and on a 100 square, they look different, but the order of counting is still the same, isn't it? We can count the numbers in two ways, so we might say four tens eight, or we might say 48, for example.

And when a number ends in nine, it is always followed by a decade number when counting in ones, isn't it? Okay, so well done.

You've worked really hard today and you've found out lots about what can help you with your counting those patterns that can help you with your counting.

So excellent, well done.