numbers natural numbers integers rational numbers numerical calculations Babylon China Euclid Diophantus Pierre de Fermat Leonhard Euler Adrien-Marie Legendre Carl Friedrich Gauss arithmetic number theory
Number theory began with the manipulation of numbers, that is, natural numbers 



(

N

)
,


{\displaystyle (\mathbb {N} ),}

 and later expanded to integers 



(

Z

)


{\displaystyle (\mathbb {Z} )}

 and rational numbers 



(

Q

)
.


{\displaystyle (\mathbb {Q} ).}

 Number theory was once called arithmetic, but nowadays this term is mostly used for numerical calculations. Number theory dates back to ancient Babylon and probably China. Two prominent early number theorists were Euclid of ancient Greece and Diophantus of Alexandria. The modern study of number theory in its abstract form is largely attributed to Pierre de Fermat and Leonhard Euler. The field came to full fruition with the contributions of Adrien-Marie Legendre and Carl Friedrich Gauss.
