Math That I Taught Myself

I wonder if x to the zero power was discovered? or invented? I tried a Google search but couldn't go deep enough to find an answer. Math formulas and proofs continually amaze me! I love how everything works together logically, but circles and slopes of lines are still quite complex in terms of all their properties. This is my third year teaching Saxon Algebra II to my homeschoolers, and I "get it" even better than before. Which is somewhat of a feat, considering that I taught myself Algebra II in high school. My dad was the principal, and he let me work independently through the book, as long as I turned the tests into the regular teacher for grading. I still like the challenge of mathematics!