Writing a book for middle schoolers requires different formatting than for older students. Many books are written for this audience, and many LaTeX book templates are available too, yet I cannot find good templates for middle school math book.
I know LaTeX is very powerful and could be used to create such a template, but it also would be very time consuming, so if one exists already....
Here is a link to an excerpt of a book for 7th graders.
Based on a few comments from marmot, I will expand with some pictures so that the question is "self-contained"