All you can do is practice! I had my calculator taken away in Gr. 12 and I haven't gotten it back yet for my math courses so it wasn't a big deal for me. But practice, practice, practice! Also, if you're using a study guide like Kaplan, just remember that some of the example questions they give are impossible to try to do quickly without a calculator, and you won't get Q's like those on the test. Also, if you try the opted.org sample test, it will give you a really good idea of the complexity of the physics and math sections.