What is a square root?
A square root of a number is a number that, when it is multiplied by itself (squared), gives the first number again. For example, 2 is the square root of 4, because 2x2=4. Only numbers bigger than or equal to zero have real square roots. A number bigger than zero has two square roots: one is positive (bigger than zero) and the other is negative (smaller than zero). For example, 4 has two square roots: 2 and -2. The only square root of zero is zero. A whole number with a square root that is also a whole number is called a perfect square. The square root radical is simplified or in its simplest form only when the radicand has no square factors left. A radical is also in simplest form when the radicand is not a fraction.