A square root is the most common root operation. A root is the inverse operation of an exponent (which means that it undoes an exponential operation), and so a square root is an operation that undoes an exponent of 2. For example,

as either “the square root of 9” or “radical 9.”

As you can see, when you take the square root of any square number, the result is the number that you multiplied by itself to get that square number in the first place. For example, to find

you ask the question, “What number when multiplied by itself equals 100?” The answer in this case is 10, because