"Things which are equal to the same thing are equal to one another." This axiom which is basis to arithmetic and algebra is given by

This is Euclid's first common notion (axiom) from his Elements, which states 'Things which are equal to the same thing are also equal to one another.' This transitive property forms the foundation of arithmetic and algebraic reasoning. Pythagoras is known for the Pythagorean theorem, Descartes for coordinate geometry, and Euler for many contributions but not this axiom.