It is hard to do math without superscripts and subscripts. Superscripts are also handy to create footnotes.
In the old days, one would use the b tag to create text in boldface font. Now, however, with HTML5, this is dangerous to use, although still supported. It was kept into the HTML5 standard along with the u tag for underlining, and the i tag for italicizing. Yet none of these tags have any semantic meaning the way that the <mark> tag does. That highlights text because it is relevant in another context, for instance in this case the phrase "semantic meaning" might be part of a vocabulary list for a classroom.
While you should avoid <b>, <i> and <u>, there are more semantic tags that you can substitute such as em (for emphatic stress) and strong (for important text). This was HTML5's way of "copping out", and allowing a bridge from an HTML littered with format tags to the HTML of the future. However, no such luck for underlining!
The author of this web site takes no responsibility for the future portability of your HTML if you use <b>, <i> and <u>. This is tagged with the small tag, which used to be added for pure formatting reasons, but now defines a "fine print" section of text.
q is the abbreviation for quoted text; whereas cite is an abbreviation of citation. Each are shown below.
I am a quotation. To Note the use of deleted and inserted text here.
be or not to be
...that is the question.
There are excellent examples of HTML5 in the Apress book, The Definitive Guide to HTML5 [Paperback]." Adam Freeman. Apress. 2011 ISBN: 9781430239604:.
Often your page might define a term, such as emphatic stress. Emphatic stress is a special stress that is given by the speaker to some word in a sentence, usually to single out, compare, correct, or clarify things.
There are lots of tags that are used to model computer programs.
var greeting = "Hello World!";
Please enter your name: Jack
An interesting element is the <wbr> element. This helps the browser know
when to "safely" break a long word. A good example of a long word is a hyperlink. Resize your
browser window to see how each of these URLs break.
URL 1: https://www.google.com/search?q=use+of+the+wbr+tag+in+html5&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a
URL 2: https://www.google.com/
search?q=use+of+the+wbr+tag+in+html5 &ie=utf-8 &oe=utf-8 &aq=t &rls=org.mozilla:en-US:official &client=firefox-a
One last thing. There is a long-since deprecated element that I never use in production but I continue to rely on when writing dynamic HTML. It is very handy to use, and I rue the day the element was lost.