I too have absolutely no idea what that may mean.
But here are comments on the wording.
It is generally accepted that the wording "n is an integer between -12 and 12" means , that is neither -12 nor 12 can be included. If we want them included write "n is an integer from -12 to 12".
The second point is the use of the word "two". Saying "x and y are two integers from -12 to 12" means . Because otherwise we would not have two but one listed twice. If we want to allow that possibility write "If each of x and y is an integer from -12 to 12..."