Choose any three by three square of dates on a calendar page...
Can you explain how this card trick works?
Take any whole number between 1 and 999, add the squares of the
digits to get a new number. Make some conjectures about what
happens in general.
Here is an example of a 4 by 4 Latin square:
Can you see what is going on?
In the grid below, N is a 6 digit number with a very special property:
if you double the number and write it in the second row,
treble the number and write it in the third row,
and so on...
you end up with a Latin Square!