Around here, especially with high school freshmen, clever is hard to come by...which is what made this one of the highlights of my week.
In case you don’t have your hawkeye powers working today the instructions say:
The missing numbers are integers between 0 and 12
The numbers in each row add up to the totals of the right
The numbers in each column add up to the totals along the bottom
The diagonal lines also add up the totals to the right