Yes, it looks exactly the same as the iOS built-in Calculator
The UI is implemented by mimicing the iOS Calculator, by inspecting its colours and button positions. On iPad, it looks like an enlarged version of the iOS Calculator
Well, there are, indeed, a lot of calculator projects in GitHub and from other sources. However, here is a list of problems this repo tries to solve:
“When they were prototyping the iPad, they ported the iOS calc over, but it was just stretched to fit the screen. It was there all the way from the beginning of the prototypes and was just assumed by everyone at apple that it was going to be shipped that way. A month before the release, Steve Jobs calls Scott Forstall into his office and says to him, “where is the new design for the calculator? This looks awful.” He said, “what new design?” This is what we are shipping with. Steve said, “no, pull it we can’t ship that.” Scott fought for it to stay in, but he knew he had to get their UI team involved to design a new look for the calculator but there was no way they could do it in that short time frame, so they just scrapped it.
LUKE DORMEHL, Cult of Mac, https://www.cultofmac.com/421893/why-the-ipad-has-never-shipped-with-a-calculator-app/
You are more than welcome to contribute!
Feel free to create an issue to discuss potential improvements, bugs, or feedbacks!
Feel free to create a PR if that’s the best way to solve a problem! And then add your name to the list of contributors.