2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/63434An extension to the factorisation principle as suggested by Fermat is presented.We start from a symmetry of natural numbers and obtain the factorisation principle therefrom.Later it is extended further to test the primality of any natural number and finally used to factorise any given number.4 pages LaTeXGeneral Mathematicstext