Thread: Rational program calling up from different file but in same package

I'm having trouble calling up the methods that are in the constructor file from the main method.
Here's the code in the main method:

 public static void main(String[] args) {
        // Create a new rational number and set it to 1/3
		Rational rational1 = new Rational();
		rational1.numerator = -1;
		rational1.denominator = 3;
		printRational(rational1); // -1/3
 
		// Create a rational number using the second constructor
		Rational rational2 = new Rational(3, 5);
		printRational(rational2); // 3/5
 
		// Negate the rational number
		negate(rational1);
		printRational(rational1); // 1/3
 
		// Invert the numerator and denominator
		invert(rational1);
		printRational(rational1); // 3/1
 
		// Convert the rational number to a double
		double decimal = toDouble(rational1);
		System.out.println(decimal); // 3.0
 
		// Reduce a rational number to its lowest terms
		Rational rational3 = new Rational(3, 21);
		printRational(rational3); // 3/21
		reduce(rational3);
		printRational(rational3); // 1/7
 
		// Sum two rationals
		printRational(add(rational2, rational3)); 
	}
 
}

All the methods are errors.
Here's my code in the rational file

public class Rational {
    int numerator, denominator;
 
 
	public Rational() {
		this.numerator = 0;
		this.denominator = 0;
	}
 
	public Rational(int numerator, int denominator) {
		this.numerator = numerator;
		this.denominator = denominator;
	}
 
	public static void printRational(Rational rational) {
		System.out.println(rational.numerator + "/" + rational.denominator);
	}
 
	public static void negate(Rational rational) {
		int numerator = rational.numerator;
		int negatedNumerator = -1 * numerator;
		rational.numerator = negatedNumerator;
	}
 
 
	public static void invert(Rational rational) {
		int oldNumerator = rational.numerator;
		int oldDenominator = rational.denominator;
		rational.numerator = oldDenominator;
		rational.denominator = oldNumerator;
	}
 
 
	public static double toDouble(Rational rational) {
		double numerator = rational.numerator;
		double denominator = rational.denominator;
		return numerator / denominator;
	}
 
 
	public static int gcd(int a, int b) {
		if (b == 0) {
			return a;
		}
		int r = a % b;
		return gcd(b, r);
	}
 
 
	public static void reduce(Rational rational) {
		int gcd = gcd(rational.numerator, rational.denominator);
		rational.numerator = rational.numerator / gcd;
		rational.denominator = rational.denominator / gcd;
	}
 
	public static Rational add(Rational rational1, Rational rational2) {
		int newNumerator = rational1.numerator * rational2.denominator
				+ rational1.denominator * rational2.numerator;
		int newDenominator = rational1.denominator * rational2.denominator;
		Rational newRational = new Rational(newNumerator, newDenominator);
		reduce(newRational);
		return newRational;
	}
}

Any help would be great!

Got it thanks!!