This book is a brief and handy guide for the use of Microsoft Excel to solve financial mathematics problems. It presents step-by-step instructions for solving the most important time value of money problems along with brief explanations of the financial theory relevant to these problems. Thus, it provides not only the how to but also the why of financial mathematics problem solving. The value of a dollar today is not the same as the value of a dollar tomorrow or sometime in the future. Thus, the principle of time value equivalence allows us to compare monetary values from different time periods. Investors and managers forecast expected cash flows from potential investment projects. Then they discount the cash flows to find their present value. Then they compare this present value to the cost of making the investment. If the net present value is positive (exceeds the cost) they make the investment. Everyone should be aware of the time value of money and the net present value decision rule.