Calculus is actually pretty easy. One thing that really surprises me is how many music majors claim they don't like math. In reality, Calculus I and Music Theory Two are probably about the same level of difficulty. Things really don't start getting ugly in the math world until you reach junior level ABET engineering courses and apply the Calculus you learn. Calculus I-III and even DiffEq generally aren't that hard depending on *where* you take them, but at some point, you will be expected to apply it and things get more difficult there. To answer your question, I'm guessing one can skate by in the world of Data Science without knowing Calculus and used pre-boxed algorithms and/or numerical analysis techniques to make observations. After all, a person can write a 3D game now without necessarily knowing classic Physics or Linear Algebra since that person can likely rely on a gaming engine to do that "hard stuff". I think much of Data Analysis these days might be in using low-level Tensor Flow or higher-level Auto ML or super easy regression analysis packages. You don't necessarily need to have a deep understanding of how these things work to use wrapper libraries. With that said, don't avoid Calculus. It's much easier than you think and there are probably software tutors out there...
