Gotta love this circlejerk. Yes, if you don't make an honest attempt at learning the material Purdue math exams will beat you into the fucking ground. Like, you have to actually learn it. You can't cram the night before. Actually you can, but only if you've been keeping up with homework so far and understand the material. Don't expect to learn all of the concepts the night before.

The exams are ten questions (or thereabouts), usually on the same difficulty as the homework or slightly harder. If you only get three right, that's not the fault of the math department, you didn't learn anything. Randomly guessing would net you two or three right answers.

And mechanically solving homework does not equal learning the concepts. You have to understand what you're doing and why you're doing it, because sometimes the exam question is phrased in a way that requires some manipulation before you can apply the calculus, and if you can only solve problems in narrow WebAssign-defined ways, you'll be up shit creek without a paddle very fast. And don't let Wolfram Alpha become a crutch. In Calc 1 and 2, you can't just throw every integral you see in there, because solving those is exactly what you'll be tested on. Once you're adept at solving integrals, and the focus is more on setting up the integral (like in Calc 3), then you can start throwing that shit in Wolfram Alpha. I don't have time to solve a whole page of triple integrals; as long as you remember enough to solve them on the exam, you can let Wolfram crunch the numbers. At a bare minimum, to be ready for an exam, you should be able to handle any random WebAssign problem thrown at you from any of the homework covered in the exam. There's also ample previous exams provided; you should be able to handle those questions too.

Purdue Math Deparment: Actually making students learn shit or fail. The As are reserved for those who have mastered the material. The Bs are for those who understand it pretty well. If you scrape by cramming for every test and not doing very well, don't be surprised when you get a C (or lower); that's what you earned.

P.S: You should have a 100% on homework and close to 100% on quizzes. Do your homework and those quizzes in recitation are fairly trivial questions copied straight from the homework (which you should have done). Having a near perfect homework and quiz score will give you more breathing room on the exam. So few people don't actually do the homework and show up for quizzes, that doing those plus a little perseverance should get you most of the way to a B.