https://www.techradar.com/news/ios-13-may-bring-a-calculator-app-to-your-ipad-for-the-very-first-time

You may not have ever noticed, but your iPad didn't come with a calculator app installed on it when you first got it out of the box.

Instead, you have to download a third-party calculator app to be able to do calculations on your Apple tablet, but according to a new rumor that's set to change with iOS 13.