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Hi everyone, it's Mr. Whitehead here, ready for your maths lesson.
I've just been taking a few moments between items on my to-do list, for a little break.
And I was looking for a photo album and came across, it's an old photo album, came across a photo I thought I would share, it is a picture of me.
Let's get the light off.
I am here.
No, here.
This is me.
I think I was in Year Five or Year Six at this time.
The other person in the photo is my brother.
I wonder how much you think I've changed since this photo was taken, it has been quite awhile since I was sat in that brown uniform.
Anyway, that little bit of time spent looking through the photo album has left me ready and focused for this lesson.
I hope that you are in a position where you were able to give me your attention for the next 20 minutes.
If you're not, press Pause, take yourself off to a quiet location so that you can sit, focus and learn for the next 20 minutes.
Press Pause.
Come back as soon as you're ready to start.
In this lesson, we will be rounding decimals that have two decimal places to just one decimal place.
We're going to start off by rounding some whole numbers, then rounding decimals to the nearest whole number.
And we can see how that is different to rounding decimals with two decimal places to just one decimal place.
All of that is going to leave you more than ready to tackle the independent task at the end of the lesson.
The things that you'll need: pen or pencil, some paper, a pad or book from school, if you've been given one and a ruler.
Press Pause, go and collect those items and come back as soon as you are ready.
Okay, let's get started.
So rounding whole numbers first of all.
A true or false activity for each of these three statements, do you agree or disagree? If you disagree, why and what would you change within the statement to make it true? Press Pause, have a go at completing the task, come back and we can check.
Let's take a look.
So show me with your fingers please, how many do you think were true? How many were false? And let's have a look then.
So the first one, 5,610 rounded to the nearest thousand is 6,000, true or false? It's true.
Second one, 505 rounded to the nearest 10 is 500, true or false? False.
Why is it false? And what would you change to make it true? Very good.
We would need to change 505 rounded to the nearest 10 is 510.
How about the last one? True or false? Yes, it is false, 6,212 rounded to nearest hundred, it's not 6,300.
What would we change? Yes, we would need to change it to 6,200, that is the nearest hundred to 6,212.
Good start.
So we've just looked at rounding whole numbers.
Let's now have a think about rounding decimals to the nearest whole number.
There's a sentence that will help you.
Here's the first one I'd like you to look at, 1.
32, a decimal with two decimal places, can you round it to its nearest whole number? Pause and have a go, then come back and we can compare our approaches.
You ready? Let's get the answer out of the way.
What is the answer? Okay, and let's now think about how we got there.
So I'm rounding the number 1.
32, the nearest multiples of one are one and two.
We're thinking which of these two is it closest to? So we plot 1.
32 in the correct position, in its correct location between one and two and we can see which is it closest to? Absolutely, it's only 32 hundredths away from one.
How many hundredths away from two is it? 68 hundredths.
So 1.
32 rounded to the nearest whole number is one.
Good start.
Here's another one, 6.
56.
So go and have a go at it, round it to its nearest whole number, come back and check.
Are you ready? So let's work through this process and we'll reach the answer at the end.
I'm rounding the number 6.
56.
The nearest multiples of one are six and seven.
Let's plot it.
Oh, it's just over half way.
6.
56, six hundredths past halfway, past 6.
5.
So which of two multiples of one is it closest to? Closest to seven? How many hundredths away from seven is it? 44 hundredths.
How many hundredths away from six is it? 56 hundredths.
So we can see that it is closest to seven.
Another, 9.
91.
Pause, go and have a go, then come back.
Are you ready? So which is, what's the answer? Okay.
Let's see how we got there.
I'm rounding the number 9.
91, the nearest multiples of one are nine and 10.
Where is it along the number line? 91 hundredths.
It's there.
Definitely closest to 10.
How many more hundredths until it is 10? Nine more hundredths.
It's closest to 10.
Really good start.
Let's just bring all of that together within the context of animal heights.
Here are some heights, of the giraffe, the camel, the rhino.
They are the heights to the precise metre.
5.
21 metres, 1.
83 metres, 1.
46 metres.
I wonder if you could round those measurements to the nearest metre.
Pause, have a go and come back when you're ready to share.
Are you ready? So tell me what would you round the giraffe's height to? Five metres, good.
The camel, closest to two metres and the rhino, closer to one metre, only just though, a few more centimetres, two more hundredths of a metre, sorry, four more hundredths of a metre and it would round to two metres.
Okay.
Let's move things on then.
What do you notice about this number line? The space between 3.
2 and 3.
3 divided into 10 equal parts.
Okay, with that in mind then, which decimal numbers could be placed on the number line? Have a go at writing some down.
Are you ready? I'm going to share with you numbers, the decimal numbers that could be placed.
So from 3.
2 to 3.
3, if it's divided into 10 equal parts, it's one tenth divided into 10 equal parts.
So each of these equal parts is increasing by one hundredth, 3.
21, next 3.
22, next, keep going.
What would you say next? Good.
Continue.
3.
27, 3.
28, 3.
29, 3.
30, 3.
3.
I wonder, based on these numbers that we've now plotted along the number line, if we can have a think about which of them would round to 3.
2? Which of these numbers would round to 3.
2? Brilliant, these pink ones would.
So which of them would round to 3.
3? Yeah, the rest of them, these green ones would round to 3.
3.
Are there any others though that would round to 3.
2 and would round to 3.
3? Have a think.
Absolutely, yes, there are some more.
We need to think about the numbers before 3.
2.
The numbers on the number line here, 3.
11 to 3.
14 and 3.
15 to 3.
19.
We've got some more numbers here that would round to 3.
2.
How many of them would? Good, five of them would, there they are in the pink.
Do we have any others that would run to three point three? Let's think bigger than 3.
3.
So between 3.
3 and 3.
4, we've got this set and this set of hundredths.
How many of them would round to 3.
3? Good, four of them would, there they are in green.
So we've been thinking here about rounding, about changing numbers that have two decimal places to only having one.
3.
34 rounded to one decimal place, 3.
3.
Whereas on this page, if we come back, 3.
19 with two decimal places rounded so it only has one, 3.
2.
Let's have a think about that now then.
We have some individual numbers.
Using this sentence to help us, the sentences to help us, 4.
56 rounded to one decimal place, what would that be? Pause and have a go, come back and we'll look together.
Should we take a look? So we're thinking 4.
56, which tenths are nearest to it? We've got 4.
5 or 4.
6.
So where does 4.
56 sit? There it is, there.
So rounded to one decimal place, it will be 4.
6.
Here's another one.
Pause and have a go, come back and we'll check.
Let's take a look.
What did you get as the answer? Okay, let's see how we got there.
So the options, the tenths that it sits between, are 6.
5 and 6.
6.
And where does 6.
55 sit? Hover with your finger on the screen.
Yes, we were right there.
Ah, so this is an example then of what? What would this round to? To 6.
6, it's halfway between the two, we round to the next, in this case to the next 10th, 6.
6.
One more.
This time it's 6.
97, what would it round to? Pause and have a go, come back and we'll look.
How did you get on with this one? Was it as simple? Little bit more thinking needed.
So important, to consider as always in this case, the tenths that 6.
97 sits between.
Between 6.
9 and seven.
To plot 6.
97 along the number line, which is it closest to? Closest to seven.
So 6.
97 rounded to one decimal place is seven.
There aren't any decimal places and that's because of the number we were rounding and which multiple of tenth it was closest to.
You are more than ready for your independent task.
Actually, no, you're not.
There's one thing I didn't say at the beginning that you're going to need, it's three dice or it's one dice that you throw three times or ask a parents or carer to help you find some virtual dice online.
You'll need those for the litle investigation that I have set for you.
Come back when you're ready to share how you got on.
How did you do? Can I see what you've been recording? How you've been recording? Get the dice out of the way.
That's it.
Oh, looking good.
I'm interested here because I had a go and I was only able to find, so I wrote it two, three, four, made these six numbers.
They rounded to one decimal place and it looked like this, I didn't manage.
I had another go as well.
I didn't manage to find any numbers that, from rolling the dice, that would end up, from the three digit numbers I created, rounding to the same numbers when rounded to one decimal place.
So for me, the questions from the task, I was only able to find numbers that rounded and ended up being six different numbers.
What about you? Did you manage to find any that could? Or were you like me and unable to? I wonder why.
I wonder what reasons there are there.
There's some more thinking to do, I think, on the back of this task.
If you'd like to share the outcomes to the task or any more thinking that you do off the back of it, please do.
Ask your parents or carer to share for you on Twitter, tagging @OakNational and using the #LearnwithOak.
Fantastic lesson, everyone.
You have certainly earned yourself a break after all of that brilliant learning and participation.
Thank you for leaving me feeling so happy and proud to have spent the last 20 minutes working with all of you.
I'm going to take a break now as well.
It's time to put this photo back in the album.
I look forward to seeing you again for some more maths sometime soon, until then look after yourselves.
And I look forward to some more maths learning very, very soon.
Bye for now.
