I would like to have a better understanding of time. I have to start at an extremely basic level, however, due to my lack of intelligence. It was suggested to me that I start with Pre-Algebra. Can someone give me a link to a free resource or a book with which I may learn what is needed to progress to the next suggested topic, Algebra I. Thank you very much for your help. Note: It isn't necessary to read this part but I felt I should clarify something. I know that there are many resources to learn something such a Pre-Algebra. There are so many, in fact, that I became overwhelmed trying to decide which source has the best explainations and completeness of material. That is why I am asking for a recommendation, so that I may feel comfortable with the completeness of the material. Also, I understand that saying "I want to understand time." is very vague but, due to my current knowledge of physics, it is the best way for me to describe what I am trying to accomplish.