It should be time to study and apply a mathematical accounting model which is easy to understand and audit, and is accurate and reliable. The paper distinctly describes three accounting's concepts or models (physical accounting model, double-entry system model, and mathematical accounting model) and their relationships. The physical accounting model naturally exists since business emerging and is the base of all other accounting models. The physical accounting model is actually consisted of every transaction which is based on a principle: exchange of equal values. The double-entry system...