BTW, the computer program Practica Musica and accompanying text are a great introduction to music theory. I didn't need the sections about reading music but the rest is very interesting.<quoted text>
I **knew** that answer was coming.
The question pertained to music theory.
If you add intervals, third and fifth, you get a seventh.
If you add a third and fourth, you get a sixth.
3 + 5 = 7 and 3 + 4 = 6.
E.g. Ascending from C to G is a perfect fifth. From G to B is a major third. Ascending from C to B is major seventh: 5 + 3 = 7.
I thought you played the piano?
It even has drills to train you ear and to learn to effectively compose melody and write music on paper after dreaming it up in your head and it's a whole lot cheaper than a college course.