A Civilization advance.
Rudimentary arithmetic first gained wide use due to farmers' and traders' need to keep track of quantities, accounts, and measurements. Eventually, clever philosophers built on this mundane base to conceive an abstract theory of numbers, which they called mathematics. Soon after, military leaders found ways to use mathematics in the design of weaponry.
Prerequisites: Alphabet and Masonry.
Allows for: The University, Physics, Computers, and Astronomy.