Abstract
The aim of this study is to explore a central topic in financial mathematics: the internal rate of return. To this end, the study begins by introducing basic concepts of financial mathematics and their possible everyday applications. As we delve deeper into the properties of the internal rate of return, we can see that its calculation is not simply based on concepts learned in primary education. Therefore, we seek to relate this science to Numerical Calculus, employing methods such as Bisection, Newton-Raphson, and Secant in order to determine internal rates of return that have been applied in payment sequences stemming from real-world financing situations.