You can add any two ints using the + operator.
~void main() {
int x = 5;
// y will be 6
int y = x + 1;
// z will be 11
int z = x + y;
IO.println(x);
IO.println(y);
IO.println(z);
~}Adding a negative number does the same thing as subtraction.
~void main() {
int x = 5;
// y will be 1
int y = x + -4;
IO.println(x);
IO.println(y);
~}