What is the shortest and most preferred way of writing the result?

Question

Let's say I have to calculate 6/4 (i know, it's simple). Would the preferred answer be 3/2 or 1.5? Same with square roots: is sqrt(2) a better answer than 2^(1/2)?

Answer 1

Answer from @Wuestenfux in comments:
No really best way here. As a hint, if the outcome is an algebraic number, write it down as such and not as a decimal number