## Lead–in #2 TimeLine 300 BCE – 1 BCE

** 300 BCE: **EUCLID

Euclid, a Hellenist living in Alexandria, Egypt publishes *Elements*, a 13–volume treatise on geometry and the ancient Greek version of number theory.

Euclidean geometry employs, among other

components:

– definitions

– postulates (axioms: highest level “laws”);

– propositions (theorems derived from postulates);

– proofs of theorems.

Euclidean geometry is a self–contained construct of mathematical and formal logic of elegance and perfection.

*Elements* has been revised in over 1,000 editions, and is considered the most successful “textbook” ever written.

** 300 BCE: **THE ABACUS

The Babylonians invent the earliest calculator, the abacus, in Mesopotamia.