Matrix Math Plus

* Although not designed as a game, It may also be used as an activity to just pass the
time, similar to a crossword puzzle except it involves numbers instead of words.

* There is no minimum or maximum age for which Matrix Math Plus has been designed.
The Settings screen allows adjusting the Starting and Ending numbers from -20 to 20,
for accommodating a range of levels.

* Negative numbers may be enabled by setting the Starting number below 0 in the
Settings screen. The Starting and End numbers are saved on exit and retrieved at startup.