<p>Hello! My high school limits us to one math and one science class per year so I could take only either AP stats or AP calculus. I ended up choosing AP stats since I large proportion of kids in AP Calc fail and ruin their GPA’s which I did not want to risk.</p>

<p>I’m getting increasingly interested in trying to change to a Chemical Engineering major which means I’d have to take 21A. How doable is 21A if you’ve never taken calculus in high school? I haven’t done any calculus related stuff since the end if junior year during the “Intro to Calculus” portion we did in Pre-Calculus. I’d say I’m good at math, but I’m not genius. I never took AP math classes, but I did well in honors ones. </p>

<p>Thanks for any input! Feel free to be brutally honest with how difficult the transition would be if you feel the need to. I understand that difficulty is subjective, but I’m mostly asking about being able to understand the concepts with no calc experience and the transition from stats back to calc.</p>

<p>Well, to get into MAT 21A, you would have to pass the math placement exam (dates given [here](<a href=“https://www.math.ucdavis.edu/undergrad/math_placement]here[/url]”>https://www.math.ucdavis.edu/undergrad/math_placement)</a>) and get a score of 35 or higher. If you get a score of 30-34, you’ll be placed in MAT 16A or 17A (the 16 series is basically considered easy Calc and the 17 series is for BioSci majors). If your score is between 25-30, you’ll get placed in MAT 12, which is Pre-Calculus. </p>

<p>My high school is a science and math oriented school so the classes prepare us well. I did the practice placement tests for math and I’m confident in my ability to get placed into at least 17A, though hopefully 21A since the placement tests seem to test basic things learned between algebra and pre-calc. Trig was always one of my favorite parts during algebra 2 and pre-calc so I know I’ll be fine on that section to get into 21A. I’m not overly worried about the placement test, mostly just the class itself. Thanks though!</p>