There is now a handy Fast Formulas Guide at the top of this blog. It summarizes the key formulas and the posts that describe them. The guide may help you see connections between the formulas.
By the way, I upgraded the math formatting for most of the Fast Formulas posts with LaTeX (thank you again to those who responded to the poll on whether to do this), and I made some of the equations more concise. One example is that instead of dividing by 
The Well-Tempered Spreadsheet 