This book exposes basic concepts of financial mathematics and project evaluation, which are illustrated with multiple examples based on real-life applications. Its approach is comprehensive, since from the presentation of the basic elements of financial mathematics it develops the indicators to measure the economic goodness of an investment project, at the same time that it delves into the construction of the cash flow to make the evaluation of an investment project or the valuation of a company, which is complemented by the analysis of more advanced topics such as the weighted average cost of capital, EVA and risk. In this new edition, several chapters have been supplemented and updated, included in the first edition, emphasizing the use of Excel in the computational part. It also includes the estimation of the efficient frontier in mean variance and the use of the CAPM to estimate the cost of the equity contribution in the calculation of the weighted average cost of capital. The problem base was broadened, including a new chapter with problems of different nature and difficulty, which summarize the typology that any professional in the financial area will encounter, especially in what is traditionally called financial mathematics; and another chapter of cases, to analyze more complex problems and illustrate the effect of different decisions, including some of financial modeling. The chapters on weighted average cost of capital are a guide for its interpretation and estimation, especially the last (new) one that raises the estimation problems in Colombia through a case.