Answer 1

Do you mean this question?
int x = 25; int y;
y = _ - 12;
System.out.println(_);
x is 25. You only can do something with y.
--> y have to be 13
--> just do the math to get 13
Solution:
int x = 25; int y;
y = x - 12; //25 - 12 = 13
System.out.println(y); //13