I'm not sure what is the difference between strong text and bold text, and small text, subscripted text, and superscripted text?

Answer 1

https://www.sololearn.com/discuss/230785/?ref=app
https://www.sololearn.com/discuss/237558/?ref=app
https://www.sololearn.com/Discuss/51341/?ref=app
https://www.sololearn.com/discuss/57739/?ref=app

Answer 2

Both <b> and <strong> make the text bold. However, <b> just makes the plain text thicker, while <strong> makes it contextual, too. Depending on the client settings, it may behave differently - people with vision disabilities will have the text marked <strong> auto-read with a lower voice, for example.

The other set of tags is a totally different story. <small> just makes the text smaller by a step, while <sub> and <sup> make the text subscript or superscript, respectively.

<sub> is used in chemical formulae notations for example (H2O, CO2) - it is the small text BELOW the main text line.

<sup> is used in mathematics - power notation of ² or ³, as well as in text footnotes, for example.