This paper surveys and generalizes the main valuation formulas used in real estate appraisal and presents unified proofs. The results are otherwise scattered in obscure journals and books while the proofs are rarely available to researchers in the field. The few benefits and many pitfalls of using internal rates of return are also summarized and illustrated. The material was originally developed so that it could be used by mathematically-trained appraisers and researchers in the former Soviet Union and in other transition economies that were starting their real estate appraisal profession.