We had some interesting responses from St. James School in Southam. UK.

James, Mathieu, Morgan and Stephen wrote:

On the large square you add $8$ to each column and on the smaller square you add $6$ each time.

Alex, Isaac, Matty and Emil wrote:

$+8$ downwards, $+9$ diagonally right downwards, $+7$ diagonally left downwards

The first box is equivalent to $22$, and then we discovered that if you plussed $8$, then that would be your next boxes answer! Following through right until the end of the larger square!