I prepare "lecture notes" while helping my daughter at home with her studies. I had earlier put these online, like other random stuff, for that Asymptotic Someone. Most of these are mere hand-written scribbles. Thinking more about it, I felt that, for now, a much better idea is to list the resources that have been helpful for me in really getting to know and love math and the sciences, rather than simply studying these topics.
Realm of Numbers, Isaac Asimov
Quick and Easy Math, Isaac Asimov
Realm of Measure, Isaac Asimov