What is a surd or irrational roots?

Irrational rootsRoots that are irrational are called surds. Irrational Numbers are decimals that neither repeat nor terminate. But not all roots are surds.

Sqrt(4) is not a surd, because sqrt(4) is + or - 2, which is rational. On the other hand, sqrt(2) is a surd, and that's because the square root of two is irrational.

A surd is a number that cannot be changed into a fraction. They go on infinitely without any pattern.