This is a task to make a simple calculator using only HTML5 and CSS3. This calculator can do addition, multiplication, subtraction, division, and modulo operation. The "eval= " attribute in tag helps us to evaluate any calculation of any given operator.
References: https://www.youtube.com/watch?v=cGgLHJGyS34
Do note there is no additional Js file as all the work is done in the HTML file only. CSS file is needed for customization of the webpages. Also, I used Bootstrap for a Navigation bar, and also to give a webpage a good look. :)