Arithmetic,  Geometry,  Music, and  Astronomy.
The Quadrivium (which pertains to Matter & Quantity)- the advanced four.
 GEOMETRY —Number in space.
The Quadrivium with Gene Odening, Gnostic Media Podcast episode #050 (start here)
Quadrivium – Number, Geometry, Music, & Cosmology with John Martineau, Gnostic Media Podcast episode #103 (intermediate)
The Golden Ratio with Dr. Scott Oslen, Gnostic Media podcast episode #108 (advanced)