- Chinese mathematician Liu Hsin uses decimal fractions.
- Heron of Alexandria writes Metrica (Measurements). It contains formulas for calculating areas and volumes.
- Nicomachus of Gerasa writes Arithmetike eisagoge (Introduction to Arithmetic) which is the first work to treat arithmetic as a separate topic from geometry.
- Menelaus of Alexandria writes Sphaerica which deals with spherical triangles and their application to astronomy.
- Ptolemy produces many important geometrical results with applications in astronomy. His version of astronomy will be the accepted one for well over one thousand years.
- By using a regular polygon with 192 sides Liu Hui calculates the value of π as 3.14159 which is correct to five decimal places. (See this History Topic.)
- Iamblichus writes on astrology and mysticism. His Life of Pythagoras is a fascinating account.
- Theon of Alexandria produces a version of Euclid's Elements (with textual changes and some additions) on which almost all subsequent editions are based.
- Hypatia writes commentaries on Diophantus and Apollonius. She is the first recorded female mathematician and she distinguishes herself with remarkable scholarship. She becomes head of the Neo-Platonist school at Alexandria.
- Proclus, a mathematician and Neo-Platonist, is one of the last philosophers at Plato's Academy at Athens.
- Aryabhata I calculates π to be 3.1416. He produces his Aryabhatiya, a treatise on quadratic equations, the value of π, and other scientific problems.