Assessment wanted for web-based exercise "Marking up a letter"

Hello.
Assessment wanted for Marking up a letter. What can be improved? Is the quote marked up correctly, or do I need to change something?
A link to the example:

Hi @derrieter and welcome to the community :wave:

Great work on you first exercise! :medal_sports:

There are some tiny things that could be improved:

  • “Tel” and “Email” also belong into the address. From the <address> article:

    … may include any type of contact information that is needed, such as a physical address, URL, email address, phone number, social media handle, geographic coordinates, and so forth.

  • effect of 3 × 10<sub>3</sub> increasing to 3 × 10<sub>4</sub>: These <sub>s should be <sup>s.
  • For the quote you don’t need to write quotes (") because the <q> automatically adds typographical quotes.
  • “The memoirs” are (probably) a book, so it would be better to remove the cite attribute and add a <cite> element around the source:
    <p>University of Awesome motto: <q>Be awesome to each other.</q> -- <cite>The memoirs of Bill S Preston, <abbr title="Esquire">Esq.</abbr></cite></p>
    

I hope that helps. Feel free to ask questions. :slightly_smiling_face:

Michael