In math, sometimes we want to calculate the percent that something changes. Percent changes are often seen in word problems and are useful in many real world situations, for example when shopping sales or when calculating a tip. A percent change is a way to describe how much a quantity increases or decreases. For example, when you buy an item with tax, the tax is the percent change from the original price to what you paid.
Percent change is an easy and quick math topic that shows up all over the SAT, the ACT high school exit exams and standardized tests. So if you want to increase your scores on those kinds of tests this is a good concept for you to tuck away in the back of your brain. It's not too hard once you remember the formula, the way to find out percent change is to do the new price take away the old price then divide that result by the old price. New take away old divided by old or new new take away the original divided by the original price. That's just a quick little formula that'll help you figure out the percent change usually involved in two dollar amounts.