This accessible and engaging textbook provides an introduction to the equations that have defined economics and shaped the global economy. It not only presents the ideas, concepts, and applications that underpin these equations, but also places them within their broader social and historical contexts. Simple mathematical examples and illustrations of the real-world application of the equations are combined with an overview of the implications to give a complete understanding of the power and importance of each equation. It will be relevant to economics students wishing to broaden their understanding of mathematics, mathematical economics, applied economics, and the history of economic thought.