I recently found out that in Windows 10 you can choose to have the calculator app always on top. However, the app that you can always on top is not the full calculator.

Full Windows 10 Calculator
Stay on top calculator

The first image is the full Windows 10 calculator which shows history and you can resize to your heart’s content.

The second image is the stay on top calculator which is gimped – it can’t be resized, it does not show history. My only request is to have the full version be able to be pinned/stay on top of all other windows.