We use mathematical symbols every day, yet few of us ever stop to ask why they look the way they do.
Why is addition represented by + rather than some other shape? Why does the equals sign consist of two parallel lines? Why is the unknown quantity so often written as x? And why do symbols such as ∞, ∫, ∑, and √ each have their own unique forms?
These symbols were not invented overnight by a single person. They emerged across different civilizations and different eras, shaped by centuries of experimentation, competition, refinement, and eventual standardization. From Ancient Egypt, Babylon, and Greece to India, the Islamic world, and Renaissance Europe, every mathematical symbol carries a story of knowledge transmission, cultural exchange, and the evolution of human thought.
Yet the true significance of mathematical symbols goes far beyond making mathematics easier to write.
Every new mathematical symbol is, fundamentally, a new cognitive tool. It enables us to compress information, organize knowledge, express abstract ideas, and extend the limits of human thought. Many mathematical concepts that seem obvious today only became possible after the symbols capable of expressing them had been invented. In this sense, the progress of mathematics has depended not only on new discoveries and new theorems, but also on new ways of representing ideas.
In this series, we journey back through history to explore the origins of mathematical symbols—from addition, subtraction, multiplication, division, and the equals sign to square roots, integrals, summation, infinity, and many more. Along the way, we discover how these symbols were created, how they evolved, and how they gradually transformed the way humanity understands the world.
As we rediscover these familiar symbols, we uncover more than the history of mathematical notation. We uncover the history of human cognition itself—and, with it, the story of civilization.