By request: if you accidentally delete the calculator app on iOS 18, you can reinstall it by going to the App Store link: https://apps.apple.com/us/app/calculator/id1069511488

(Calculator appears to only show up in the App Store on the iPhone, not the iPad, for now)

‎Calculator

‎Do the math with Calculator from Apple. Features • Use the standard calculator in portrait mode, or turn your device to landscape mode for more advanced calculations using the scientific calculator. • Quickly access Calculator in Control Center. Swipe down from the top-right edge on iPhone X and…

App Store