For an example of what the page in the first photo is referring to, here's the top web search page for a scale I was playing today on guitar https://ianring.com/musictheory/scales/3419
That's what they call music theory. It's what I would call number theory applied to a musical scale. I have no idea how any of that exquisitely beautiful "theory" can be of use to me in musical practice. Do you?
For an example of what the page in the first photo is referring to, here's the top web search page for a scale I was playing today on guitar https://ianring.com/musictheory/scales/3419
That's what they call music theory. It's what I would call number theory applied to a musical scale. I have no idea how any of that exquisitely beautiful "theory" can be of use to me in musical practice. Do you?