I don't know what does this mean exactly.
without needing graduate-level math
Does this mean you don't need to know about high-level math?
Graduate level math is probably referring to graduate school in college/higher education. Someone who gets their graduate degree has either their masters or doctoral degree. When it says they don't need graduate level math, they are talking about math classes that would commonly be taken by someone who is acquiring a graduate degree. Follow this link for some more information about graduate school
A full sentence would be helpful. For example,
I can balance my checking account without needing graduate-level math.
It means basic math skills are sufficient to solve the problem.
This kind of statement can be used to de-emphasize the importance of a given skill (in this case the value of graduate-level math).