# Lesson video

In progress...

- Hi, everyone.

How are you doing today? I'm Miss Mitchell, and today in maths, we're going to be estimating length in centimetres.

In today's lesson, you will do a Do Now.

You will then have an input about estimating in centimetres.

You will then complete a worksheet and then a quiz.

For today's lesson, you will need small objects of different size.

For example, a pen, a book, some pasta, a piece of paper, but please make sure you ask a parent or carer before touching these items. You'll also need a pencil and some paper and perhaps a ruler.

For your Do Now, I would like you to tell me whether these sentences are true or false.

The height of the classroom door is less than one metre.

So, is the height of your classroom door less than one metre? True or false? The length of a car park is about one metre.

The width of a teacher's whiteboard is about a metre.

The length of your arm span is more than one metre.

Let's see how you got on.

So, the first one, your classroom door is less than one metre.

False.

The length of a car park is about a metre.

False.

Car parks are really big.

The width of a teacher's whiteboard is about one metre.

True.

So, obviously everyone's whiteboard will be a little bit different, but they are roughly a metre.

And finally, the length of your arm span is more than one metre.

So, your arm span is when you hold your arms out to the side.

It's the length, the distance between your fingertip on one hand to the fingertip on your other hand.

Now, if you do that now, do you think that's more than one metre? True.

And little fun fact for you, your arm span is actually the same as your height.

There you go.

Fun fact of the day.

So, today, we're going to still be focusing on standard unit of measurement, but this time it will be centimetres.

Can you say centimetres? Now, there are 100 centimetres in one metre.

Let me say that one more time so you really remember that.

There are 100 centimetres in one metre.

So, we use centimetres to measure smaller items, things that are less than one metre.

And we measure in centimetres to make it more accurate because if everyone uses the same unit of measure, it will be a lot more accurate than using perhaps hands, measuring in hands or pennies.

So, everyone measures in centimetres.

Today, you're going to be estimating the length and height of objects in centimetres.

So, we are estimating.

Can you remind me what does the word estimate mean? That's right.

You're making an educated guess, an educated prediction, a judgement.

So, today you're going to be estimating objects in centimetres.

Now, this is the length of a ruler, and a ruler is 30 centimetres.

So, ruler starts at zero and ends at 30.

So, this is 30 centimetres.

Now, if you have a ruler in front of you, you may want to look at what 30 centimetres is.

Now, I have this plant here, and I'm going to estimate the length of this plant.

Now, I have a ruler.

I know it's going to be less than 30 centimetres.

I know it's going to be less than 30 centimetres.

I even think so.

What's half of 30? What's half of a ruler? That's right.

15 centimetres.

I even think it's going to be less than that.

So, I think that the plant is going to be about 10 centimetres.

And I think that because I think it's less than half of a ruler.

So, I predict that this plant will be about 10 centimetres.

For your independent task, I would like you to estimate the length of your objects in centimetres.

So, you are guessing the length.

Remember, centimetres, you can write it in short for cm.

So, if you think it's 10 centimetres, you would write 10cm.

Pause the video and have a go.

And here are some examples of my estimations.

Now, remember these are just examples and yours will be different.

Yours will be different because you would have estimated different objects, and your estimations will be different to mine.

If you have a parent or carer around, perhaps you can ask for them to check your answers.

Great work today.

You worked really hard.