Just remember: an octave goes from frequency X to frequency 2*X, there are 12 semitones per octave, 1, 3, 5, 6, 8, 10, 12 are a major scale and 1, 3, 4, 6, 8, 9, 11 are a minor scale. Traditional notation is garbage because it looks as if the semitones in c major / a minor were more important than those in between, which they are not. That's pretty much all one needs to know to avoid the pitfalls of music theory.