What is the use of <sub> and <sup> tags

Question

In html the output of:- small text, subscripted & superscripted all looking same then why we use <sub> and <sup> ??

Answer 1

1. Html <sub> tag defines subscript text. Subscript text appears half a character
below the normal line, and is sometimes rendered in a smaller font. Subscript
text can be used for chemical formulas, like H2O.
2. Html <sup> is used for superscript text like it represents 2 cubed and 4 square in
mathematics