Answer:
See explanation
Explanation:
I wouls say to my friend that he is incorrect, because there are infinitely many pairs of numbers with a difference of 12.
For example,

Here we can increase the first and the second number by 1 and get their difference equal to 12 after this operation.
The same is possible with negative numbers:

Actuall, we can do this with decimals too

Such pairs of numbers are infinitely many (because there are infinitely many real numbers) and we cannot find all possible numbers with difference of 12.