On November 27, 1852, Augusta Ada King, Countess of Lovelace, who is considered to be the world's very first programmer, passed away. Every student of computer science should have heart of the world's first programmer, Ada Countess of Lovelace, assistant to Charles Babbage, inventor of the very first programmable (mechanical) computer, the analytical engine.
On March 3, 1845, German mathematician Georg Cantor, creator of the set theory was born Set Theory is considered the fundamental theory of mathematics. He also proved that the real numbers are "more numerous" than the natural numbers, which was quite shocking for his contemporaries that there should be different numbers of infinity.
F. Arzarello, M. Bussi, and O. Robutti. Proceedings of the 28th International Conference of the International Group for the Psychology of Mathematics Education, 4, page 89-96. (2004)