Adding Fractions in java

AddingFractions.java

import java.io.*;
import java.util.*;

/*
 * To execute Java, please define "static void main" on a class
 * named Solution.
 *
 * If you need more classes, simply define them inline.
 */

class Solution {
  
  private static double gcd(int a, int b){
    if(a == 1 || b == 1){
      return 1;
    }
    if(a == b){
      return a;
    }
    if(a > b){
      return gcd(a-b, b);
    }
    return gcd(a, b-a);
  }
  
  private static double lcm(int a, int b){
    return (a*b)/gcd(a, b);
  }
  
  private static double add(int num1, int den1, int num2, int den2){
    
    if(den1 == den2){
      return (num1+num2)/den1;
    }
    
    double ans = (num1*den2 + num2*den1)/lcm(den1, den2);
    
    
    int ans1 = (int)num1*den2 + num2*den1;
    int ans2 = (int)lcm(den1, den2);
    //print in fraction form
    System.out.println(ans1 + " / " + ans2);
    
    return ans;
    
  }
  
  public static void main(String[] args) {

    Scanner s = new Scanner(System.in);
    int test = s.nextInt();
    while(test>0){
      
      int num1 = s.nextInt();
      int den1 = s.nextInt();
      int num2 = s.nextInt();
      int den2 = s.nextInt();
      
      System.out.printf("%.2f", add(num1, den1, num2, den2));
      test--;
      
    }
    
  }
}