Calculating percentages is a skill that most people first encounter in middle school math classes, but the necessity for understanding percentages continues for many years beyond school. If you've ever been shopping, you probably have seen signs that announce a certain percentage off particular items. In order to determine exactly how much money you would have to spend to make the purchase, you must be able to calculate how much the discount is worth.

Convert the percentage into decimal form by dividing by 100. For instance, if something is 25 per cent off, divide 25 by 100 to get 0.25.

Multiply your answer from Step 1 by the total price of the item. For instance, if the item is £26 at 25 per cent off, multiply 0.25 times £26 to get a discount of £6.

Subtract your answer from Step 2 from the original price of the item to figure out the amount that you would have to pay if you bought the item at the current discount. For example, £26 minus the discount of £6 means that you would pay £19 for this item.