* '''19''' - [[Evariste Galois]] develops [[group theory]], and wrote it out completely on the eve of his death at age 20; it took old [[mathematicians]] a century to comprehend it.
* '''19''' - [[Evariste Galois]] develops [[group theory]], and wrote it out completely on the eve of his death at age 20; it took old [[mathematicians]] a century to comprehend it.
* '''19''' - [[John D. Rockefeller]] starts a new company, turning an enormous profit in its first year, and became the most influential businessman in history.<ref>http://www.notablebiographies.com/Pu-Ro/Rockefeller-John-D.html</ref>
* '''19''' - [[John D. Rockefeller]] starts a new company, turning an enormous profit in its first year, and became the most influential businessman in history.<ref>http://www.notablebiographies.com/Pu-Ro/Rockefeller-John-D.html</ref>
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* '''19''' - [[Steve Jobs]] begins collaborating in electronics with Steve Wozniak<ref>http://www.ideafinder.com/history/inventors/jobs.htm</ref> in electronics, and developed the personal computer within two years.
* '''19''' - Mark Zuckerberg develops Facebook, the leading social networking system for young people on the [[internet]].
* '''19''' - Mark Zuckerberg develops Facebook, the leading social networking system for young people on the [[internet]].
* '''20''' - Carl Friedrich Gauss makes his first mathematical discoveries, which will lead to the completion of "Disquisitiones Arithmeticae", his magnum opus, at the age of 21.
* '''20''' - Carl Friedrich Gauss makes his first mathematical discoveries, which will lead to the completion of "Disquisitiones Arithmeticae", his magnum opus, at the age of 21.