Kwon Kim Ca is correct. Let me explain this step by step-
Basically a standard cube has 6 sides each labeled with the numbers 1,2,3,4,5, and 6. You asked for the probability of rolling a number greater than 4 on a standard cube. 1,2,3, and 4 is less than 4 or equal to 4 so that wouldn't work. 5 and 6 are the only numbers that are greater so add up the total amount of numbers :1,2,3,4,5,6! 6 numbers!
so 6 would be the denominator and 2 would be the numerator because there are 2 numbers greater than 6.
All in all,
2/6 is the answer and simplified?: 1/3.
Hope this helps!