The root of a real or complex number is a number that, when raised to some exponent (or multiplied by itself the number of times indicated by the exponent), equals the original number. Most people are familiar with square and cube roots. There are actually many other such roots, including the real fourth roots, real fifth roots, and so on, and roots associated with complex numbers. For example, the real fourth roots of 16 are 2 and -2; the real fifth root of -32 is -2.