Hi, I am an Independent Advisor.
Tap on Windows logo plus R to open run box, on the Run box type in %WinDir%\System32, scroll down and look for calc.
Right click Calc and then send to Desktop, Right click calc from the desktop and then click on Properties, then on the click on the Shortcut key box then enter the Keyboard shortcut you want to set for it, click Apply and then click OK.
I attached a screenshot for your reference.