Lesson video
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Hi everyone, It's Mr. Whitehead here, and ready for your maps lesson.
Are you ready? Are you feeling calm? Are you collected? Are you ready to focus? If the answer is yes, that must mean you are in a quiet space.
Have a look around you.
It must mean that there aren't any distractions waiting to go off and steal your focus.
If however, as you're looking around, you're noticing a television, a tablet, a game close by, I think it's time to pause.
Move into a quieter space so that you can keep your focus, develop your mathematical skills and knowledge, and understanding with me for the next 20 minutes.
Pause while you get yourself sorted, and then come back as soon as you're ready to start.
In this lesson, we will be rounding decimals with two decimal places to the nearest whole number.
We're going to start off with a rounding whole numbers activity, before we think about why we round, then we will look at rounding those decimals to the nearest whole number.
That will leave you ready to practise those skills in the independent task.
Things you're going to need, pen or pencil, a ruler and some paper, a pad or a book from school, if you've been provided with one.
Press pause, go and collect what you need, come back and we'll start.
Okay, getting started then.
We have some rounding of whole numbers through a true or false activity.
Press pause, read each statement, and decide if you think it's true or false, and to give some reasons for why.
If you think it's false, what changes would you make so that the statement were correct? Come back when you're ready.
How did you get on? How many of them do you think are true? How many are false? Okay, let's look then.
So true or false.
The first one, 4,320 rounded to the nearest thousand is 4,000, true or false? That one is true.
Next one, 325 rounded to the nearest 10 is 320, true or false, it's false.
What changes would you make? 325 rounded to the nearest 10 is 330, good.
Last one, 4,764 rounded to the nearest hundred is 4,700, true or false? It's false, what changes would you make? Fantastic, so it should say 4,764 rounded to the nearest hundred is 4,800.
So there's a little bit of rounding to get us started.
Why and when do we round numbers? We've just had a little practise in that activity, but beyond maths and beyond activities in our maths lesson, when would we use these skills? I've got a couple of sentence starters that might help you.
When I'm shopping.
When I measure a.
Have a little think.
How might you finish those sentences? Are you ready to have a look together? So these are the ones I came up with.
When I'm shopping, I might say that something which costs one pound 99 is about, it's approximately two pounds.
So I'm going to round there.
Another example, when I measure a pencil, instead of saying it's 18.
7 centimetres, I might say it's about, or it's approximately 19 centimetres long.
So a couple of examples there, where we give approximate lengths, amounts instead of the actual.
So let's have a think then about rounding to the nearest whole number.
First of all, what do we mean by whole numbers? 0.
7, 7/10, seven, which of those is a whole number? Which of them are not whole numbers? Good, when we're thinking about whole numbers, seven is the example from those three.
We're rounding to the nearest whole.
So looking at this.
3.
4 rounded to the nearest whole number.
what's it going to be? Do you have any ideas? Let me talk you through the thinking that should be happening.
I wonder if what I say is what you were thinking.
When we round to the nearest whole number, we need to think about the options that we have.
3.
4, it's either going to round to three or to four, which one it rounds to is dependent on how far away it is from each of them.
3.
4 sits here.
It's closer to three and further from four.
So we say 3.
4 rounded to the nearest whole number is three.
Here's one for you.
I want you to think about this sentence as you try this problem.
7.
6 rounded to the nearest whole number.
Draw a number line.
Mark on the options.
Mark on the nearest multiples of one.
Where does 7.
6 sit? How does that help you make your choice? Come back when you're ready.
Have you got to solution? Have you got some reasons? Compare your number line to mine.
So I've gone for one looking like this this time rather than a number stick.
And 7.
6, so I'm thinking if I'm rounding 7.
6, the nearest multiples of one are seven and eight.
So where does 7.
6 sit between seven and eight? There it is.
It's closest to eight and furthest from seven.
So can we say the sentence together? 7.
6 rounded to the nearest whole number is eight.
Good work, here's another one.
5.
5 rounded to the nearest whole number is.
So again, pause.
Maybe draw the number line and mark its location between the two nearest multiples of one, or visualise the number line.
The number line is a step.
You could just visualise it now.
See it in your mind's eye.
Come back when you're ready.
Ready, so what's the answer? Okay, how did you get that? Good, so here you may have visualised a number line like this, either the track or the number line.
And we're thinking about those two nearest multiples of one, five and six.
Now 5.
5, interesting sits here, which is 5.
5 closest to? Which multiple of one is it closest to? It's halfway between the two.
It's halfway between five and six.
We can't say it's closest or furthest from either of them.
This is an example, and you're used to this from rounding with whole numbers.
When we're dealing with a number that sits halfway between the two options we round to the next multiple, whether that's a multiple of one, 10, 100 and so on.
So the answer here, you're right, is six.
Say that whole sentence for me from the bottom, on three.
One, two, three.
5.
5 round is six, well done.
Okay, a little pause.
So you have some options on the left of choosing decimals.
I would like you to round your chosen decimal to the nearest whole number.
Use the sentences that are on the screen right now, to help explain your thinking.
Perhaps choose three, four, five.
When you feel like you've had enough practise, stop and then come back and play again.
How did you get on? How many of those numbers did you round to the nearest whole? Oh, you were busy? I worked on three.
So this was one that I picked.
I rounded the number 70.
4.
What are my nearest multiples of one? 70 and one.
And 70.
4 is closer to 70, therefore rounded to the nearest whole, it is approximately equal to 70.
I also had a go at this one.
I'm rounding the number 7.
6.
Fill in the blanks for me, the nearest multiples of one are zero and one.
So zero, not a multiple of one.
So actually that senses us need to change a little bit.
I could talk about it being between zero and one.
Which is it's closest to? 0.
6 is closest to one.
Therefore rounded to the nearest whole, it is approximately equal to one.
The third one I tried, 8.
5.
Finish the sentences.
Fill in the gaps.
I'm rounding the number 8.
5.
The nearest multiples of one are eight and nine.
The number is closer to, when it's not, we can't finish that sentence.
It's halfway between the two.
So because of it being halfway between, we say 8.
5 rounded to the nearest whole is approximately equal to nine.
Those were the ones I tried.
I wonder which ones you had to go at.
I hope you enjoyed it and were able to successfully round those numbers to the nearest whole.
Let's have a look at another one.
See if you can spot something that's different here.
4.
32 rounded to the nearest whole number is.
What's changed here? We're now looking at decimals with two decimal places and not one.
I wonder what this will round to as the nearest whole.
If you want to pause and have a go at working on it, then come back and we'll look at it together, do that now, or stick with me and we'll work through it at the same time.
Ready, so similar thinking's needed.
4.
32, which are the nearest wholes? The nearest multiples of one that it lies between? Four and five, okay.
So where does it sit?.
32, 32/100 is going to sit around here.
Which of the two multiples of one is it closest to? Closest to four.
So 4.
32 rounded to the nearest whole number is four.
It's closest to four.
It's 32/100 away from four.
How many hundreds away is it from five? It is 68/100 away from five.
So it's closest to four.
Next one, which is the closest whole number? 5.
55, have a go at this one.
Do press pause.
Have a go, then come back and check.
Ready, so what are our options? Could be five, could be six.
Where does 5.
5 sit? 5.
55 sits, it's there.
It's over halfway.
So which of the two multiples of one is it closest to? Excellent, read the sentence for me.
5.
55, six, brilliant.
We'll learn more.
This time 4.
49.
Pause, have a go then come back and compare.
Are you ready? So, which are our options? Which multiples of one does 4.
49 sit between? Good, four and five.
Where does it sit on that number line? Almost halfway 100th away from 4.
5.
Which of the two multiples of one is it closest to? Brilliant, read the sentence to me.
4.
49 rounded, good work.
It's time for you to have a practise now using these skills in your independent task.
So press pause go and complete it, then come back and look at the solutions.
Are you ready to check? Okay, hold up your paper.
I want to see how you approached recording this because you had all of these circles that you were recording within.
So show me how you tackled it.
Looking good, it's looking organised and systematic, and very mathematical, well done.
So I had to go too and where the target was to fill each of the circles with two numbers.
You managed almost all of them, but zero to four, seven and nine.
I need a second number.
Can you give me another number for each of those circles? Give me another number for zero.
Maybe from your list that I could have filled in that would round to zero.
That's good, so that number is closer to zero, not one.
Give another one that could go into two that would round to two.
Good, give me one that would round to four.
Can you give me one that would round to four that would have a three in the ones place, and a four in the ones place.
Good, how about seven? Give me one that would have a six in the ones place, and a seven in the ones place, good.
And one more for nine.
It can have a nine in the ones place, and it would round to nine.
Nine is closest, good.
I would be really interested in seeing your learning from this session, looking at those circles with the numbers filled in.
Please, if you would like to share it, ask your parents or carer to help you by sharing your learning on Twitter, tagging @OakNational and using the hashtag LearnwithOak.
Everyone, that was brilliant.
I really enjoyed that lesson.
Thank you for participating, contributing and fully engaging with all of those activities.
I hope you have a really big smile on your face.
It's really well deserved.
If you've got any more learning lined up for the day, please take a break first.
You need it.
I would say I'm taking a break before I do anything else.
That's for sure.
I look forward to seeing you again soon for some more maths, until then look after yourselves, and I will see you soon, bye.
