# Natural Numbers

*If we had twelve fingers,*

*it would be much easier for us to understand*

*how the numbers are ordered.*

introduction to theory of numbers

**There are seven primary, separate, subsets of the set of Natural Numbers:**

**N = {2, 3, 5, 7} ∪ N2 ∪ N3 ∪ N5 ∪ N7 ∪ Pu ∪ (Pu x Pu)**

**Pu = (P ∪ {1}) \ {2, 3, 5, 7}**

1

**Ordering of Natural Numbers:**

**Set (Pu ∪ (Pu x Pu))**