9/90 as a percentage is 10.00%. This simple fraction reduces to 1/10, which is a tidy way to see why the percent comes out to a round number. When you see 10.00%, you know it represents one‑tenth of a whole.
The fraction 9/90 can also be thought of as nine parts out of ninety equal parts. Because each part is the same size, the ratio stays the same no matter how you look at it. That’s why the decimal form is 0.10, and the percent form is exactly ten percent.
In everyday use, saying “10 %” is often enough, but writing 10.00% shows the precision to two decimal places. It’s a handy way to communicate small differences when you need an exact figure, such as in school projects or quick calculations.
