Why html 5 is necessary isn't html was fine i use to learn html but not html5?

Question

html 5. vs. html

Answer 1

HyperText Markup Language (HTML) is the primary markup language for web pages. 
HTML5 is the version of HTML.
There are lots of differences that are given in HTML5.

The main difference between HTML and HTML 5 is that video and audio are not part of HTMLwhile these both are integral parts of HTML5 specifications.

-from web.

Answer 2

HTML5 is much more interactive than HTML. Transitions, transformations and animation. In combination with CSS3 provide great opportunities without using JS. You're able to create attractive, interactive pages, new original controls using clear HTML5+CSS3.