This book reinforces an understanding of Economics by showing how basic mathematics is used to construct models of the economy. By taking wide-ranging examples drawn for virtually all areas of economics, it shows how model-building is an indispensable aid to understanding economics.The mathematical techniques used in the book are fairly rudimentary -- optimisation methods and equation-solving are the primary tools used. A brief explanation of constrained optimisation using Lagrange multipliers is provided. Throughout, the emphasis is on how these techniques are fruitfully deployed in constructing economic models and solving economic problems. It bridges the gap between mathematical analysis and economic logic. For readers, it builds confidence in constructing their own models for purposes of analysis. The book is well-suited for self-study.