Wire sizes

[usmcpop]

http://en.wikipedia.org/wiki/American_wire_gauge

The first is the number of the gauge - the thickness of the main conductors. The second is the number of main conductors. There usually will be a ground wire in addition to the main conductor wires. So you end up with a spec like "10/3 with ground".

[ZnUSA]

Can someone decode the wire sizes for me. I see things like 10/3 alot and just want to know what it means and what other sizes I might need to know.
Thanks