I would say both are very important to be an Actuary. For mathematics, the important part is your process of solving a problem. Calculus and proof-based classes such as Real Analysis teach you how to go from a set of assumptions to a final answer through a “logical” process. For instance, you are given all sorts of information in the question and you need to somehow derive the answer. This skill is not only important in the day to day work for an Actuary, but this skill is needed to pass Actuarial exams. Once you come up with your answer, you’ll often need to make recommendations based on your analysis. This train of thought is tested heavily with the FSA written exams. So yes, Mathematics teaches you this skill and is very important.
Statistics is also very important to do the day to day work. If you are an Actuary, you’ll likely be working with a lot of data. Big data I might add. You need to make sense of your data to build your models. When you are developing your models, you’ll first need to explore the data and see how it behaves. This is where Statistics comes in where you’ll look at the distribution, P-values, Regression, Time Series etc. You’ll need to determine which variables are important in your data to help build actuarial models. You’ll also be trying to “correlate” your data with the external environment. Actuaries call this external factors. Statistics will help you make conclusions on how the external environment impacts what you are trying to model.
Sign up for the All-Around course where you’ll learn the foundational skills to do entry-level actuarial work. You’ll get to practice how mathematics and statistics come into play to do Actuarial work.