This textbook concisely covers math knowledge and tools useful for business and economics studies, including matrix analysis, basic math concepts, general optimization, dynamic optimization, and ordinary differential equations. Basic math tools, particularly optimization tools, are essential for students in a business school, especially for students in economics, accounting, finance, management, and marketing. It is a standard practice nowadays that a graduate program in a business school requires a short and intense course in math just before or immediately after the students enter the program. Math in Economics aims to be the main textbook for such a crash course.The 1st edition was published by People's University Publisher, China. This new edition contains an added chapter on Probability Theory along with changes and improvements throughout.