On screen calculator

Some Calculator Apps, such as PCalc, can be used with iPadOS Slide-over or Split Screen modes - thus keeping the Calculator on-screen whilst working with other Apps that also support iPadOS multitasking.

PCalc can be downloaded from the App Store:

https://apps.apple.com/gb/app/pcalc/id284666222

You may find these overview Apple video guides to be helpful:

After viewing, you’ll be ready for the additional Multitasking Guide:

Use Multitasking on your iPad - Apple Support

The iPad User Guide for iPadOS is also a rich source of information. Here are links to both the downloadable and online versions of the Guide:

‎iPad User Guide on Apple Books

iPad User Guide - Apple Support

I hope this explanation and additional information is helpful in resolving any difficulties you may be having with Multitasking features of your iPad.

K-119 wrote:

That was exactly what I needed. Thank you!

You’re very welcome.

PCalc is only one example that support multitasking features of iPadOS - but is, of itself, one of the better Calculator Apps offering advanced functionality and regular updates.

Just so know.

There are many calculator apps that support Slide Over and Split View window modes.

A calculator app I use, is called Digits.