I want to write a simple textbook on standard high-school level algebra.
Most of what we know about the field, we have known it for centuries. So I'm fairly certain the majority, if not the entirety, of the material to be presented in the text will be part of the open domain.
However, with that being said, it is crucial to mention that I don't remember every single theorem from the field so I will have to consult other texts and resources for compiling the book.
My question lies here. While the theorems may be read from other books, the knowledge is fairly general and well known. This is somewhat of a sticking point in Mathematics. If for example I want to talk about the precedence of the order of operations, it would unfeasible to trace back the development of this idea throughout history and all the notable mathematicians who have worked on it. This becomes more of a problem when I might have to cite texts/resources I've referenced for every trivial theorem. And then, there's also the issue about finding references for theorems and information that I feel is well known and can be considered "general knowledge."
I deeply respect and honor giving everyone due credit for their hard work; I'm just unsure how this is commonly done and accepted for writing math textbooks. I want to have a completely fair yet manageable balance between citing information and actually writing the text itself.
I'm completely new to writing textbooks; though my education and work in the field of math has inspired me to help and contribute to what has meant so much to me in my life.
I am deeply grateful to anyone who can help guide me on this new endeavor. If there are other legal issues that I should know of, I would be delighted to hear about them.
P.S. I am new to this SE site, so I'm not sure exactly what tags will be appropriate here. So please feel free to edit my question.