That all depends on the keypad!

You have described a keypad that gives an ASCII Code output when you press a button.
There are many types of keyboards that give their outputs in many different ways; eg, they might give you the X-Y coordinates of the key within the key matrix; a PC keyboard gives a "scancode" that identifies each key, etc, etc,...

You will have to consult the Data Sheet for your particular keypad to confirm exactly what output it gives.


It might help if you avoid speaking of ASCII "values" - just say "codes".
IF you avoid calling it a "value", you might find less risk of thinking about doing arithmetic with it!?
Just a thought.