public void subtract(Rational r1, Rational r2) {
int s = (r1.getNum() * r2.getDen()) - (r2.getNum() * r1.getDen());
int s2 = r1.getDen() * r2.getDen();
num = s;
den = s2;
}
public void divide(Rational r1, Rational r2) {
int d = r1.getNum() * r2.getDen();
int d2 = r1.getDen() * r2.getNum();
num = d;
den = d2;
}
public void add(Rational r1, Rational r2) {
int a = (r1.getNum() * r2.getDen()) + (r2.getNum() * r1.getDen());
int a2 = r1.getDen() * r2.getDen();
num = a;
den = a2;
}
public void multiply(Rational r1, Rational r2) {
int m = r1.getNum() * r2.getNum();
int m2 = r1.getDen() * r2.getDen();
num = m;
den = m2;
}
