As the person above you stated, he wanted to take the test again. I would honestly go out and buy officer candidate test books and ASTB books from a book store or Amazon. I found that the repetition of practice tests helped.
The actual ASTB felt relatively close to the practice test, I think that taking the actual test added stress, thus makes it harder. I also found the math to be hard for me personally, but doing the problems over and over certainly helped me with time. Just prep for the test, you will do great. Feel free to message me if you have any other questions.
I have been practicing for the math problems from my GRE test prep book. Albeit I took the GRE several years ago, I would say that the math problems in the GRE and ASTB are similar. The math in the GRE is a bit larger and covers a wider range, then the ASTB, but nonetheless it helps. As well the math on both tests is not really focusing on the solving itself, but more so you know the shortcuts to retrieve the correct answer. Does that make sense? That's why these tests are timed. I take my test tomorrow and I feel as though the resources here, the practice tests, study guides and books all helped. Thank you!