Don't count your fingers, use this calculator instead :)
Live demo here: ➡️ Vanilla JS Calculator
Written in vanilla JavaScript, HTML, CSS. I used CSS grid system for this project. While writing JS part, I intentionally not used built-in eval() function, I wanted completely implement my own solution. You can chain multiple calculations like: 30 + 12 * 3 - 1, also It's working with decimal points. There is functionality to use it with a keyboard or mouse (in mobile touching).
I also ported this project to React. If you want to see React.js version of this project, click here