How can I figure out what percentages to use in word problems?

Always remember that all the information you need to find the answer is in the word problem. It is always helpful to write out essential numbers at the top of your working so that you can better visualise the scenario, and maybe even draw diagrams. With percentages, especially where a specific amount hasn't been discussed in the question, take care to note down the changes in values and quantities that are talked about in the scenario. These changes will be the information that you will be expected to use to find the percentages you may have to later use to solve a word problem.As a general formula, the difference in value of something, divided by its original value and multiplied by 100 is the percentage change, but be aware that this may not always be the case.