In mathematics, a surd is a value in square root that cannot be further simplified into whole numbers or integers. Surds are irrational numbers, and examples of surds include √2, √3, √5, etc. . Any number of the form n√a, which cannot be written as a fraction of two integers, is also called a surd. Surds arise naturally in a number of applications, such as in the solution of quadratic equations using the formula. There are different types of surds in mathematics, including simple surds, pure surds, similar surds, mixed surds, compound surds, and binomial surds. Rules for working with surds include that surds cannot be added or subtracted, but they can be multiplied and divided.