18/20 = 90%
A score of 18 out of 20 on a quiz is 90%, which is usually considered excellent. You might also see a value like this in survey results, product ratings, attendance records, or a battery that is nearly full.
To picture 18/20 quickly, imagine a row of 20 equal boxes with only 2 left empty. It is close to the whole amount, so you can estimate it as about nine-tenths or just under 100%.
A common mistake is thinking 18/20 is the same as 18%, because both numbers appear in the fraction. The denominator, 20, represents the total, so the fraction describes most of the whole rather than a small portion.
