Answer:
By comparing, I'm assuming you mean greater than, or equal to, or less than.
To understand that let's get two irrational numbers.
Let's use pi, (3.14159265358979...) and square root of 2.
It's just like doing normal compares. I recommend trying to put the number in decimal form (if its not already in it for it is much easier.)
Square root two = 1.414....
Pi = 3.14159..
Since the unit of pi is greater than square root two, we know pi is greater.
Hoped this helped ya, if this is not the answer you expected, please clarify on what you mean by "compare" in the comments. :)