It is a specialized form of the Newton method ... For example, suppose you wanted to take the square root of 85. You can observe that 9 squared is 81, so the answer is sort of 9, right?

Roots are the opposite of powers. As 2 squared is 4, then a square root of 4 must be 2. \(2^2 = 4\). Reversing this gives \(\sqrt{4} = 2\). To find square roots or cube roots, work backwards from ...

One way to do this is to use a grid: The four terms cannot be simplified because each of the surds has a different number inside the square root, and none of the surds can be simplified.