Disclaimer - I haven't taken the GRE in about 6-7 years.
From what I remember being told, the GRE's math portion is high school math. Think like algebra, trig and geometry. If they made it for college level, only math majors would pass. The way the test is done now is on the computer and it changes the questions it gives you depending on if you answer the question right or not. If it's right, you get a harder question. And if it's wrong, you get an easier one next.
You'll have to take the writing part, right? Definitely read up on how they grade that part. When I took it, I read that takers should stick to the 5 paragraph essay style.