This manual is written to accompany the third edition of Mathematical Interest Theory by Leslie Jane Federer Vaaler, Shinko Kojima Harper, and James W. Daniel. It contains solutions to all the odd-numbered problems in that text. Individuals preparing for the Society of Actuaries examination in Financial Mathematics should find that the detailed solutions contained herein are an invaluable aid in their study. As in the main text, it is presumed that the reader has a Texas Instrument BA II Plus or BA II Plus Professional calculator available and instruction in its efficient use to solve these problems is included.