Lesson video

Hello, everyone.

It's Mr. Millar here.

Welcome to the second lesson on percentages and in this lesson going to we're going to be looking at converting percentages to decimals.

Okay, so hope that you're all doing well to start off with.

And for the try this task, we've got three pictures and different amounts have being shaded.

So I want to give that fraction of the square that's been shaded I want you to give that as a fraction and also as a percentage and a decimal.

So for example, if we were looking at the first one I could see that the square has been split into 10.

And so I know that my denominator is going to be 10.

And I can see that four yellow strips have been shaded in.

So my fraction is 4/10, which I can actually simplify to 2/5 by dividing by two.

So I need to give that as a fraction and also a percentage and a decimal for each of these three shapes.

So pause the video and have a go at the try this task.

Great.

So let's go through the rest of these.

So first of all, the second one.

Well, you could've counted up a hundred in total and 25 that've been shaded in.

So it's going to be 25 over a hundred.

You could have also noticed that this is a five by five square.

So I'm going to have 25 there.

I don't need to count all of them.

And same thing for the larger one at 10 by 10.

So anyway, 25 over a hundred simplifies to a quarter and I've got two fifths for the last one which doesn't simplify.

And as a percentage, well I know that 4/10 is 40%.

25 over a hundred is 25% because percentages are over 100.

And 2/5, well that's also 40%.

That's the same as the first one.

And then decimals.

Well, it's going to be helpful to look at the fractions over 10 or over a hundred again.

So 4/10 is going to be 0.

4.

25 over a hundred is going to be 0.

25.

And same thing for the last one as well.

And it's going, converting between decimals and percentages that we're going to have a look at in more detail in this lesson.

So once you're ready let's have a look at the connect task for today.

Okay, so here's a connect task.

Let's have a read of what it's saying.

So we can represent decimal values and equivalent percentages using a place value table.

So the table below should look very familiar to you.

You've got tens, ones and then the decimal point and then tenths, hundreds, thousandths, et cetera.

And what we've got here is we've got some decimals that we are going to convert to a percentage.

So let's have a look at the first one, 0.

4.

Have a think, what would that be as a percentage? Well, you can imagine- You know that percentages are out of a hundred.

So you can imagine there's basically a missing a zero here.

So you can imagine that there is 40 hundredths.

So that is going to be 40%.

The next one should be quite nice and straightforwards.

0.

43, well that is 43 a hundredths.

So that is going to be 43%.

What about the next one? Because we got three in the thousandths column here.

So how do you think we would deal with that as a percentage? Well, three thousandths is going to have to- We're going to have to involve some decimals within our percentage here.

So it's actually going to be 46.

3%.

And the reason for that is the first one the four here, is going to be the tenths the six is going to be the hundredths and then we have to have a decimal point and then we have to have the thousandths here.

So let's just do one more.

So if I gave you 0.

6 uh, 0.

364, what would that be as a percentage? Well, that would be, again, a 36.

4 percentage.

And have a think, can you think of two more which can be represented on this number line going from 40 to 50%? Have a think, what decimals can you have here? Well, anything that starts off with 0.

4 something is going to lie in this here.

So 0.

43 would work.

And if I want to take another one, say something here 0.

445 would also work here.

So anything that starts off with a four in the tenths column would also fit on this number line.

Okay, let's go to the independent task now.

Okay, so for this independent task the first thing that you have to do is for each of these six letters you need to write them as a decimal.

Use the place value chart to help you.

It may make sense to go back to the previous slide in case you're stuck.

And then, second question.

You're going from a percentage back to a decimal.

So the first one, 30%.

You know that's equal to 0.

3.

So you're going from a percentage to a decimal.

Pause the video now to have a go at these couple of questions.

Shouldn't take you any more than four or five minutes to do these.

Okay, great.

And we're going to have a look at the answers on the next slide.

So here are the answers and pretty straightforward on the whole.

You'll notice that for some of these we have a decimal within the percentage as we had a look at in the previous slides.

So for example F, if I look at that down here that's going to be between 21% and 20.

9%.

So in the middle, it's going to be 20.

95% which as a decimal is going to be 0.

2095.

A common misconception that I sometimes see is to have two decimal points within our decimal.

So, for example, you couldn't have 0.

209.

5.

You couldn't have two decimal points within the same one.

Anyway, let's move on to the explore task to finish.

Okay, so for the explore task we have got a place value chart, and we've got four cards and I want to place all four cards in the four spaces and then convert it to a percentage.

So for example, the first one I could have 0.

022.

That would make sense to have as my first one and as a percentage, well that is going to be 2.

2%.

So there's actually five more for you to have a think about.

Remember you are using all five of these cards.

And have a think.

Can you get all five different combinations? Pause the video now and to have a go at this one.

Okay, great.

So hopefully you got all six of these or the five remaining ones and if you didn't, here are the answers.

So you've got 0.

202 and then you've got 0.

220.

And those are all the ones- You notice that I've gone for all the ones that start off with a zero.

Those are all the possible combinations.

And once I've done those, I start off with a two.

So 2.

002 2.

020 and finally 2.

200.

And my percentages, well I'll just run them down quickly.

It's going to be 20.

2%.

You're going to have 22% for the next one.

And the next one, I've got a two in the ones column.

So I'm actually going to have 200.

2%.

Next one is going to be 202%.

And finally 220%.

So you notice a few things going on here.

First of all, whenever I have a two in the thousandths column you'll notice that I have a decimal point.

2 in the percentage column but I don't have that when I have a zero in the thousandths column because obviously that won't count in my place value.

So anyway, hope that you got all six of these and that is it for today's lesson.

So thanks very much for watching.

And next time, we're going to have a look in more detail about some conversions between percentages and fractions.

Thanks very much for watching.

Have a good day and bye-bye.