What are the sections marked with yellow circles (with +-*and division operator within) ?

Hi,

I wanted to study up to Linear Algebra ( to better understand my coding field of machine learning), and now thinking about doing statistics before the Precalculus section, so I'm wondering in which order to take statistics lessons and what does the "Statistic and Probability" unit "badge" means ( the one explained in the title of the q) ?

Would it be better just to go through precalculus and calculus first as well?

Thanks!