Teacher talks: Video playlist

[THEME MUSIC]

[SCHOOL BELL RING]

Hello, I’m Mr McPartlin, and together we are going to explore using a number line to 100 and to 1000.

A number line is a line with marked intervals on it. Often there are numbers placed on the line.

But a number line can also appear with no numbers or markings on it.

We call this an empty number line.

We find number lines everywhere.

Rulers, scales, tape measures.

Even a clock is an example of a number line. It’s just a number line, but in a circle.

Number lines are super helpful.

They help us to order numbers, count, and to know the relative positions of numbers to each other.

Pretty handy, hey?

We can put any types of numbers on a number line. Fractions, decimals, really big numbers.

This number line starts at zero and ends at 100.

It shows numbers in jumps of ten.

Let’s count together.

Ten,

20,

30,

40,

50,

60,

70,

80,

90,

Now, let’s remove all the numbers

to play Guess The Number!

So, how do you play?

Coming up.

An arrow will point to a part of the number line, and you need to estimate which invisible number the arrow is pointing to.

Ready?

Let’s try the first one together.

Remember, this number line represents the numbers from zero to 100.

To help you, let’s highlight where the middle of the number line is.

Because this line is from zero to 100, this halfway mark represents 50 on our number line.

Using this handy hint, what number do you think the arrow is pointing to?

Let’s take a look together.

The arrow is pointing to 20.

If you said any number near that, that is excellent.

Firstly, we know that this number must be under 50.

Then, if we were to divide what’s left of our number line by half, that would be 25, which is still just a little higher than where the arrow is pointing to.

So, 20 must be our answer.

Let’s have another go.

Here is our number line

with multiples of ten on it.

Now, let’s remove the numbers and add an arrow.

What do you think this number could be?

You might even want to draw your own number line on a piece of paper to help you.

Ready for the answer?

Brilliant!

The arrow is pointing to 60.

We can see that the number line is closer to 50 than 100.

I also know that halfway between 50 and 100 is 75.

And this number is closer to 50 than 75.

Shall we take it up a notch?

This time our number line has numbers from zero to 1000.

Now, let’s remove the numbers because leaving them up there would make this too easy.

And there’s our arrow.

What number do you think is here on the number line?

Remember, you can pause if you need some more time.

First off, ask yourself:

Is our missing number more than or less than 500, the centre of our number line?

It’s less than that, isn’t it?

But only a little bit.

So, the missing number is 400.

Nice one.

You can continue this game at home.

Find anything with a number line and challenge yourselves to guess the number.

You can make it as easy or as difficult as you want to.

Have fun.