"Four Fifths" refers to a fraction that represents four parts out of a total of five equal parts. In simpler terms, if you divide something into five equal sections, four fifths means you have taken four of those sections. This fraction can also be expressed as 0.8 in decimal form or 80% in percentage form, making it easier to understand in different contexts. For example, if you have a pizza cut into five equal slices and you eat four of them, you have consumed four fifths of the pizza. This concept is useful in everyday situations, such as when calculating discounts or understanding portions in recipes, where knowing how much of something you have is important.