Hand up, I failed precalc twice and never made it past high school. But give me a blank SQL query where I can use window functions on a large dataset, I will tease out the differentiating variables that matter to a business. I think I missed the point of precalc. I never had to solve any real world problems, and the jargon was too impenetrable. Grouping and summarizing sets within sets is like, piece of cake. Just as is formal logic. The way it's taught is completely upside down.