Year 12 Mathematics students have been working over recent weeks on one of the most interesting and practical topics in Mathematics: the applications of derivatives. Through this content, they have been able to see how a mathematical tool goes far beyond calculations and can be used to interpret and solve real-life situations. During the sessions, students learnt how to use derivatives to study the behaviour of functions, analysing aspects such as increasing and decreasing intervals, the location of maximum and minimum points and points of inflection. These concepts are essential for understanding phenomena related to economics, business and the social sciences. In addition to the theoretical content, students worked on problems applied to contexts closely connected to their academic pathway, such as the analysis of business profits, cost optimisation and the evolution of certain economic variables. Through these activities, they developed strategies to interpret data, propose solutions and justify their results in a reasoned way. This work has not only helped to strengthen mathematical skills but also encouraged critical thinking and the ability to connect classroom learning with everyday situations. Once again, mathematics is presented as a useful tool for understanding and analysing the world around us.