When you were younger, you were probably sent out into the school car park at some point, to **count the different colours** of cars.

You likely used this information to draw a bar chart or something similar.

Now we have progressed from bar charts, we can use this type of information in lots of ways, such as to find **percentages**.

**Percent **means **out of 100**.

Writing a percentage, means writing something as a number **out of 100**.

**e.g. Imagine that the school car park has 100 cars and 26 of these cars are blue. **

To write this as a percentage, we say **26 out of 100** are blue, therefore **26%**.

If there were **43 blue cars** in the same car park, this would be **43%**; **19 blue cars** would be **19%**; etc.

But what happens if there are not 100 cars in the car park?

**e.g. Suppose there were 50 cars and 8 of them were green - what percentage are green?**

We know that 8 out of 50 cars are green, but it would be far easier to calculate the % if there were 100 cars.

Let's make it 100 cars then...

We need to multiply **50** by **2** to get **100**, and** whatever we do to one part of the question, we have to do exactly the same to the other part.**

So let's multiply **8** by **2** to get **16**.

This is easier now...

**16** out of **100** cars are green, so that is **16%**.

If we cancel down 16 out of 100, we get back to 8 out of 50, so we know this is correct.

**Take note:** You many also need to cancel the 'out of ' down to reach 100.

**e.g. What is 52 out of 400 as a %?**

We would divide both numbers by **4 **(as 400 ÷ 4 = 100) to get 13 out of 100 = **13%**.

**Now for the tricky part...**

The 'out of' may not be that simple to convert.

**e.g. What would we do if we wanted to write 8 out of 32 as a percentage?**

**32** obviously does not multiply up to **100**.

Could we multiply it up to** 200**?

The best way to find out is divide **200** by **32** to see if it goes into it equally.

What did you get?

A decimal number, not helpful really.

Let's try another option... how about **300**?

Another decimal, not great.

Keep going until it works... try 400, 500, etc.

In this case, our best bet is **800** - phew! I thought we were never going to get there!

800 divided by 32 = 25

Now multiply 8 by 25 which gives us 200.

We now have 200 out of 800.

To turn 800 into 100, we need to divide by 8 and then do the same to the 200.

Did you get **25%**?

Magic!

In this activity, we will find percentages of one number out of a total which we may or may not need to convert so we can equate it to 100.

Look out for a **magical tip **halfway through to give you an alternative method and a speedy shortcut!

You may want to have a calculator handy so that you can concentrate on practising these methods and not stretching your mental maths brain.