Both the ACT and SAT can cover an entire year of Algebra 2, so how should you approach preparing for the ACT and SAT if you are a junior who is currently taking Algebra 2?

The first step is to take a practice math ACT and/or a practice math SAT to get some idea of your baseline score.

 If your baseline is fairly close to your target score (less than 3 ACT points or 50 SAT points), you should consider starting your preparation early.  There is a good chance you can fill enough gaps in your math to reach your target before the end of junior year.

 If your baseline is much lower than your target (more than 3 ACT points or 50 SAT points lower) and you are getting: B’s or better in honors Algebra 2 or getting A’s in regular Algebra 2, I think the best approach is to start preparing around mid-year.  Chances are that the faster pace of the honors course and your ability/hard work will enable you to cover most of what you need to hit your target score by the end of the school year.

If your baseline is much lower than your target (more than 3 ACT points or 50 SAT points lower) and you are taking regular Algebra 2 and getting B’s or C’s, I think the best approach is to wait to start your math preparation in the third quarter.   That should give you enough time to get a respectable score by the end of the school year, but you should not be surprised if you continue testing in the summer or fall as well.