Answer:
The difference is always 1.
Step-by-step explanation:
For the top left operation, we have

For the top right

For the bottom left, we have

Finally, for the bottom right operation, we have

We notice that the difference of numbers in all operations is 1. Furthermore , at the top left, we have 2*2, then to top right we have 3 * 3; to bottom left 4*4; to bottom right 5*5.
In other words, the top expression in operations starts from 2 * 2 and goes to 5 *5.
Similary, for the expressions at the bottom of the operation, we start from 1 * 3 at top left and end at 4 * 6 at bottom right. Meaning the mulipicand on the left increases by 1 as we move from one operation to another.