The fraction 81/99 is equal to 81.82% when converted to a percentage and rounded to the nearest two decimal places. This percentage represents how much of a whole the fraction represents. In other words, if you had 99 equal parts of something and took 81 of those parts, you'd have about 81.82% of the total.
To put this into perspective, 81/99 is pretty close to 4/5 or 80%. It's just a tiny bit more than that. This means if you're dealing with 81 out of 99 of anything - whether it's questions answered correctly on a test, days attended in a school term, or slices of pizza eaten - you're looking at a little over four-fifths of the total amount.