If you apply to a highly selective college, you may need the SAT Math Subject Test. Although the test comes in two categories--Math 1 or Math 2--many colleges will only consider the Math 2 Subject Test as fulfilling the requirement.
Why is that? Because the Math 1 Subject Test is too similar to the math tested on the SAT and ACT tests. The Math 2 Subject Test covers more advanced material than either the ACT or SAT, so you will need to study for the test. If you are not very good at Math, you could pick another topic to fulfill the Subject Test requirement.
Every year I have multiple students who earn a perfect score on the Math 2 Subject exam. And almost everyone I prepare attains a 700+ on the exam (assuming that the student is already a pretty good math student). How do they do it? Well, my students take the following steps.
The two books that I use with my students are McGraw-Hill's SAT Subject Test Math Level 2 and the College Board's Math 2 Study Guide. The first one reviews all of the necessary concepts with five practice tests (and a great diagnostic tool for each one to help students identify weak areas). The second book has two official College Board exams. Do these "real" practice tests AFTER you have studied for the exam in the McGraw Hill book.
Too many students assume that the exam covers similar content as the SAT or ACT. Even if you scored highly on the Math sections of the ACT or SAT tests, you still need to specifically study for the Math 2 Subject Test. The Math Subject Test is a specialized test, covering algebra, geometry, advanced algebra and trigonometry, and pre-calculus. And, like the SAT, some of the problems can be a little tricky and using could math "reasoning" skills really helps.
Note: I know that the Barron's Math 2 Subject Test is very popular on Amazon. In general, I do not find the Barron's books very helpful. Often the books contain TOO much information and the practice tests are not comparable to the real exam. My favorite is the McGraw-Hill Math 2 Subject Test book because it gives a good review, solid practice tests, and diagnostic tools to target studying. All of my students have used this book with good success.
This is my favorite "trick" for this exam. What many students do not realize is that to get a perfect score a student does NOT need to get every question correct. In fact, a student can skip almost 10% of the questions and still earn a perfect score (assuming the other 90% are correct). This is a great advantage because a student does not waste time answering difficult questions but insteads selectively skips those questions.
Remember: The questions on the Math Subject Test are generally listed in order of difficulty, so try NOT to skip the early questions. Save skipping for the harder ones at the end. And there is a guessing penalty. So stick with the general rule, just like the SAT, if you cannot eliminate at least two answer choices, then it might be better o leave the question blank.
In May and June, when most students take the Math Subject Test, everyone is busy with finals and AP exams, and the Subject Test preparation often gets overlooked. Try not to fall into that trap. High scores on the Subject Test can really set you apart from other applicants. With my students, we typically start preparing for the Math Subject Test about 6-8 weeks before the actual exam. Students set aside about 2-3 hours per week to review the material and take practice tests. So, it can be done, if a student pre-plans a little.
I know I am repeating myself here, but even students in advanced Math, like AP or honors, still needs to study for the Math 2 Subject Test(see book recommendations above). My students are very smart, many taking AP Calculus (or higher) and scoring 5s on the AP exams, and yes, they need to study. Why? Because some of the Math they haven't seen since freshman year and to learn the test format. The Math 2 Subject Test has lots of problems that look easy but deceptively tricky.
Timing can be difficult as well. The test has 50-questions in 60 minutes, so you do the math. That is only a little over a minute per question (why Tip #2 is so important).
Not many colleges require the Subject Tests, but many still "recommend" them. Some colleges, like the University of California, strongly recommend the Subject Tests for certain majors (like engineering or life sciences). Scoring well on the Subject Tests can be a great boost to the application.