Oh God, the nay-saying. Take all these "I dunno"'s elsewhere, and don't convert them to "it can't be done"'s. It's that simple.
:Repeat Ans or K=45 or 2>abs(5-abs(5-abs(K-83
:If Ans and 7T+7≠length(Str1
L1 and L2 are stored rather than A/B/X/Y. This supports decimal points and negation, and is limited to up to 6 characters per x, and up to 12-length(x) characters per y. CLEAR erases progress for the entire coordinate. A syntax error and 2:Goto will divert to the homescreen instead of the editor. Really though, if you consider the sequence of key presses for these inputs, it's identical to the following:
Ask yourself whether bells and whistles is worth hindering efforts to solve the problem.