Custom on-screen numpad with a backspace capability
I'm trying to create a custom numpad on a mobile screen (like venmo/squarecash). I haven't had any issues creating a keyboard that let's me input numbers 1-9, a decimal, and limiting the characters after the decimal to 2 characters max (x.xx) via individual hotspots, but I haven't been able to create a delete button to remove the most recently entered character.
One concept I've been playing with, but haven't fully gotten to function yet, is utilizing the variables and on every tap of a key, save the current amount as a variable (or invisible text box), then using the "backspace" key to input the variable into the displayed amount. Thus, the backspace wouldn't function so much as a delete, rather, it would work as a "revert to the second to last thing I entered."
Any help would be appreciated.