The fraction 45/81 is equal to 55.56% when converted to a percentage. This means that if you had 81 items and took 45 of them, you'd have about 55.56% of the total. It's a bit more than half, so you can think of it as having a little over 5 out of every 9 items.
In everyday life, you might see this percentage in various situations. For example, if a student got 45 questions right out of 81 on a test, their score would be 55.56%. Or if a basketball player made 45 out of 81 free throw attempts in a season, their free throw percentage would be 55.56%. It's a useful fraction to know, especially when dealing with things that come in groups of 9 or 81.
