Yo,
I'm graduating from the BSc Marketing and Management course this July. Is the module you are worried about called "Introduction to accounting and finance"? (Not sure if they've changed it since I started the course). If so, it isn't too bad. I had a preliminary maths test in the first few weeks of university, which I did badly enough on to warrant a semesters worth of "extra maths" seminars. They were pretty helpful, and it wasn't so much that I sucked at maths, more that I had a gap year and so hadn't had to study maths since GCSE. I ended up passing the module with an average of 85 or something, which is one of the highest I've had in three years at uni, so it's definitely doable!
Hope this helps, feel free to message me if you have any more questions about the course, I'd be happy to help!