If you find yourself having Windows 10 Apps crashing, this can help you fix it. A full reinstall is more reliable, but if you don't want to go through that, you can do this and it might work. Do these in order and then after each numbered step try the Calculator to see if it worked.

  1. If you are able to open MS Store, open MS Store > Click on your profile picture on top right and sign-out. Then sign-in again.

  2. Uninstall and Reinstall Calculator app - First press the Windows Key+X > Click Windows Powershell (Admin) and then copy the line below and paste it into Powershell and press enter to uninstall the Windows Calculator:

    Get-AppxPackage Microsoft.WindowsCalculator | Remove-AppxPackage

    And then reinstall the calculator by entering this into Powershell:

    Get-AppxPackage -allusers Microsoft.WindowsCalculator | Foreach {Add-AppxPackage -DisableDevelopmentMode -Register “$($_.InstallLocation)\AppXManifest.xml”}

    (If there is a problem during reinstall, you can always reinstall from the MS Store)

  3. Run the Windows Store Apps Troubleshooter - Windows Key+X > Click Settings > Click Update & security > Click Troubleshoot > Scroll down to the bottom > Click Windows Store Apps > Click Run the Troubleshooter

  4. Reset Windows Store through Command Prompt - Type cmd in Windows Search box > Right click on Command Prompt > Run As Administrator > Type WSreset.exe and click Enter > Reboot your computer

  5. Re-register All Store apps (You will get many Reds, ignore them) - Windows Key+X and then start Windows Powershell (Admin) and then Copy the following from below and right click in Powershell to paste then press Enter:

    Get-AppXPackage -AllUsers | Foreach {Add-AppxPackage -DisableDevelopmentMode -Register "$($_.InstallLocation)\AppXManifest.xml"}

    Then Restart your PC

  6. Uninstall & Reinstall Store - Windows Key+X then Windows Powershell (Admin) and then copy the following from below and right click in Powershell to paste and then press Enter:

    Get-AppxPackage -allusers *WindowsStore* | Remove-AppxPackage

    Copy the following from below and right click in Powershell to paste and then press Enter

    Get-AppxPackage -allusers *WindowsStore* | Foreach {Add-AppxPackage -DisableDevelopmentMode -Register “$($_.InstallLocation)\AppXManifest.xml”}

    Reboot your computer

If none of that fixes it. You are basically on your own! Do a "Reset this PC" in settings after backing up your files and cross your fingers!