18/80 as a percentage is 22.50%. This fraction can be reduced to 9/40, which still represents the same part of a whole. In everyday terms, it means just under a quarter of something.
The value 22.50% is useful when you need to compare parts of a whole in a more familiar way. For example, if you scored 18 points out of a possible 80 on a quiz, you earned 22.50% of the total points.
Knowing both the fraction 18/80 and its percentage form helps you switch between exact ratios and easier‑to‑read percentages, whether you’re working on a math problem or looking at a simple statistic.