Answer:
Taking square-root of numbers
Explanation:
The reason is that the square-root of most numbers is an irrational number because the answer we have can not be written as p/q form. For example, if we take the example of √2 then the answer we have is "1.4142135623730950..." which can not be written in p/q form. Hence taking square-root of numbers will most likely give an irrational number.