I recently was doing the Mathematics for Machine Learning specialization on Coursera, which consists of 3 courses. I was always trying to get deeper into Calculus, Algebra, but I was never satisfied with the quality of different materials I stumbled upon in the past and never really went with my studies far. But then this series of courses happened and I was never more motivated to learn those concepts. I enjoyed it so much. It lies a quite solid mathematical foundation under concepts of Machine Learning. Every bit of the course is applied instantly into practical settings and there are plenty of exercises in Python. I didn't know Python much before, but I programmed in C++ and a bit in JS. I studied it in the meantime. W/o that my interest in Machine Learning was merely learning some high-level functions w/o any knowledge about underlying maths and statistics involved. Treating Machine Learning as a black box that you barely know how to modify and what impact do those modifications have is dangerous in real-life settings. I'm glad I got a deeper grasp of the inner workings and I want to recommend this series of courses to everyone who starts studying Machine Learning.