50% of 20 = ?

Explanation

In mathematics, a percentage is a number or ratio expressed as a fraction of 100. It is often denoted using the percent sign, "%", or the abbreviation "pct." For example, 45% (read as "forty-five percent") is equal to 45/100, or 0.45. Percentages are used to express how large or small one quantity is relative to another quantity.
Percentages are usually used to express values between zero and one.