This document outlines 5 common notions or axioms related to magnitudes and quantities. The notions state that: 1) Things that are equal to the same thing are equal to each other, 2) Adding equals to equals results in equal wholes, 3) Subtracting equals from equals results in equal remainders, 4) Things that coincide with each other are equal, and 5) A whole is greater than any of its parts.