This appears to be a question about entering a problem using radical notation.  There is a tool button for "square root" or "cube root" entries but the most flexible way to enter radicals is using exponential notation. 

For example, "x^(1/2)" is "the square root of x".  An entry "x^(5/3)" is "the cube root of x raised to the 5th power".  The use of exponential notation is normally used in more advanced mathematics classes.  The rules for working with radicals are exponent-based.

It is a good habit to develop because the rules for working with radicals are exponent-based. For example, it is simpler to evaluate "(2)^(2/3)*(2)^(7/3)" than it is to evaluate an expression using radical notation that is equivalent to "the cube root of 2, squared, times the cube root of 2 raised to the 7th power". In this example, using rules of exponential notation (multiplication of terms, common base, therefore add the exponents), the answer is easily determined to be (2)*[(2/3)+(7/3)] = (2)^(9/3) = (2)^(3) = 8.