<p>This is how the exams are structured:</p>
<p>Calc AB = first semester of calculus
Calc BC = first and second semester of calculus</p>
<p>If one’s school structures their courses like this, then of course taking both courses doesn’t make sense. Some schools, however, structure their courses like this:</p>
<p>Calc AB = first semester
Calc BC = second semester</p>
<p>Here, you obviously need to take both (or self-study BC while taking AB >_>).</p>