Welcome to this deck on percentage change. Percentages are a huge part of everyday maths, from shopping in a sale to understanding bank interest. We'll cover three key skills: finding a percentage of an amount, using decimal multipliers for increases and decreases, and tackling reverse percentage problems.

First, let's quickly recap how to find a percentage of an amount. The most reliable method, especially with a calculator, is to convert the percentage into a decimal and then multiply. For example, to find 40 percent of an amount, you would multiply by 0.4.

Now, let's look at percentage increase. When you increase an amount, you start with the whole original amount, which is always 100 percent. If you increase it by 10 percent, you add that on, giving you 110 percent of the original.