You can subtract any two ints using the - operator.
~void main() {
int x = 5;
// y will be 4
int y = x - 1;
// z will be 1
int z = x - y;
IO.println(x);
IO.println(y);
IO.println(z);
~}Subtracting a negative number does the same thing as addition.
~void main() {
int x = 5;
// y will be 9
int y = x - -4;
IO.println(x);
IO.println(y);
~}