Drag the Tile into the active area when editing the Quick Settings menu in order to use it. Tap on the tile to launch the floating Calculator, you can also drag it around your screen. You can use the calculator to perform simple math operations such as adding, subtracting, multiplying and dividing, while the app you had open still works as normal.
You are able to download the installer of Calculator 3.1.4 for free and have a look at users' reviews on Droid Informer. The app runs on Android 7.0 and above. This application is totally safe to download. Florian Möhle is the developer of the tool which can be found in the Productivity category.
Over 10K users installed Calculator and its most recent update was released on Sep 23, 2020. The overall user rating of the app is 4.7.