Sometimes we need to work out percentage changes.

This helps us work out a **percentage profit**, or in the case of our friend here a **percentage loss**.

This is one of the areas where we have to learn a formula - obviously, our friend here didn't learn it!

So here goes:

Percentage change = |
Actual change |
× 100 |

Original amount |

**e.g. Imagine you put £2500 in the bank 3 years ago, and now it is worth £2850 - lucky you!**

**Using this formula, how can you work out the percentage change?**

First, let's find the actual change:

2850 - 2500 = **£350**

Now substitute this value into our formula.

Percentage change = | Actual change |
× 100 | = 350 |
× 100 = | 14% increase |

Original amount | = 2500 |

Basically, that is all we need to do - we just need to learn the formula.

Don't worry you will have plenty of practice using this in the rest of this activity, as we apply the formula to find percentage increases and decreases.

You may want to have a pen and paper handy to record your working, so you can compare what you have with the examples written by our maths teacher. You will also need a calculator.

At least you made a profit in this example!

Let's see how we get on in the rest of this activity...