ABSTRACT
Number Theory is the study of numbers, in particular the whole numbers 1 , 2 , 3 , … https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781003177036/f0af01d0-3a24-4c34-9b44-c23e4a0fe932/content/math1_1.tif"/> , also called the natural numbers. The set of natural numbers is denoted by ℕ. Leaving aside the unit 1, these numbers fall into two categories: The indivisible numbers 2 , 3 , 5 , 7 , … https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781003177036/f0af01d0-3a24-4c34-9b44-c23e4a0fe932/content/math1_2.tif"/> are the primes, and the rest 4 , 6 , 8 , 9 , 10 , … https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781003177036/f0af01d0-3a24-4c34-9b44-c23e4a0fe932/content/math1_3.tif"/> composed of primes, are the composite numbers. The following basic facts, with proofs, about these numbers were already known to Euclid around 300 B.C.
