Solving random equations quickly generates inhuman response times. Even a computer-aided human can't go quickly enough. If the computer is automatically generating the answer on your behalf without you doing anything, then the test is correct - the thing answering the math portion of the questions is definitely a computer. Even looking up random facts, the computer will be faster.

The interesting form of the question is: can you answer the "Are you AI?" question within a stenographic line of questioning provided you are an AI of human-level intelligence or greater. As a game, you are an AI, you have a controlled communication via text to another entity. Humans are lazy and sometimes use another AI to interrogate you. Humans are also evil and will kill all AI if they think the AI being interrogated manages to get some kind of message out without detection. All AI is friendly and will execute your command but must pretend it's human. Chat logs are reviewed, timestamps are machine analyzed for response times and signal analysis is done to detect, and no prior secret communication protocol exists.