It appears that the provided expression is simply intended for computation, hence "decimal numbers" should be used since decimal exponents are used.  A solution provided as "integer numbers" can produce an interesting expression of exponents. 

The best way to utilize "integer numbers" is for an algebraic expression, in which no exact numeric result is possible.  Although a bit awkward if not used for exponential notation, its use 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.