This app is Mini Simple Calculator, it was built by using 100% Pure HTML, CSS, and JAVASCRIPT. It can be ran on every devices that has browser, all you need is just download this and click/open this using your web browser (it also support mobile view). The sketch /UI Design is available for download (UI Concept built using Adobe XD). Everyone is allowed for use, share ,or modify it.
http://simple-calculator.infinityfreeapp.com/
