"Arithmetica" is a mathematical work written by the ancient Greek mathematician Diophantus around the 3rd century AD. It focuses on solving algebraic equations and is considered one of the earliest texts on algebra. The work introduces methods for finding integer solutions to equations, which are now known as Diophantine equations. The text is notable for its systematic approach to problem-solving and its use of symbols, which laid the groundwork for future developments in mathematics. Arithmetica has influenced many mathematicians throughout history, including Fermat and Euler, and remains a significant reference in the study of number theory.