👉 In mathematics, a surd is a number that contains a radical expression. A radical expression is an expression containing a square root, cube root, fourth root, or fifth root of a number. For example, 25 can be written as √25 which equals 5 because 5 squared (which is 5
5 = 25) is equal to the value of √25.
A surd is a number that contains a radical expression and it cannot be