surds means: Mathematicians often find solutions that include root signs. These could be cube roots or square roots. Some numbers that have a root sign can be dealt with easily because they are exactly decimalized Sqrt16 is 4, while rt38= = 2. sqrt11.56 is 3.4 and rt5132 = 0. Because each one of these numbers are rational. (in Community Dictionary, added by Riley Hodges)