Euclid's "Common Notions"

Common notions can also be defined as axioms.

Euclid's Common Notions are found within his 13 books of "The Elements", written when he was in Alexandria. Euclid's Elements are essentially 13 books with all the geometry and other random mathematical junk they had when he was living.

Some common notions are listed below, along with where they are from:

If not x = y, then x > y or x < y. I.6

If x < y, then x + z < y + z. I.17

If not x > y, then x = y or x < y. I.19

You get the point. They are notions that are decently obvious.

The Fifth of these common notions was the Parallel Postulate. It says that within a two-dimensional plane, for any given line $l$ and a point $A,$ which is not on $l,$ there is exactly one line through $A$ that does not intersect $l.$