An Introduction to the Mathematics of Finance by J J McCutcheon (Professor Emeritus, Heriot-Watt University)
There is a concise but thorough treatment of the basic compound interest functions, nominal rate of interest, and the yield (or internal rate of return) and there are many examples on discounted cash flow. Also discussed are applications of the theory to capital redemption policies (with allowance for income tax, capital gains tax and index-linking), and consumer credit calculations. The final chapter provides a simple introduction to stochastic interest rate models.