What is the main difference in the SAT Reasoning Test and the SAT Subject Test. I really have to take my SAT asap and before I register for them I needed to know which one to take and why?
I’d say that you should look at the SAT Reasoning Test (“SAT I”) as the minimum requirement unless you’ve already taken some other generally accepted achievement test. The SAT Reasoning Test is the “basic” test and measures your overall knowledge and skill.
There are 20 different SAT Subject Tests (in 5 categories). Each of these tests measures your knowlege in only one specific subject area. You can take up to 3 of these tests on one test date. In my opinion, you should look at these tests as supplementary to the SAT Reasoning Test. Many (but not all) colleges and universities either require or recommend taking SAT Subject Tests, so if you decide to take some of them, your decision should be based mainly on the admissions requirements of the universities you’re interested in attending.
I don’t think you can do the SAT Reasoning Test and SAT Subject Tests on the same test date.